Midfield transmitter systems

ABSTRACT

Generally discussed herein are systems, devices, and methods for providing a therapy (e.g., stimulation) and/or data signal using an implantable device. Systems, devices and methods for interacting with (e.g., communicating with, receiving power from) an external device are also provided.

RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.16/435,073, filed on Jun. 7, 2019, which is a Continuation of U.S.patent application Ser. No. 16/004,894, filed on Jun. 11, 2018, which isa Continuation of PCT Patent Application Number PCT/US2018/016051, filedon Jan. 30, 2018, which is herein incorporated by reference in itsentirety and which claims the benefit of priority of the following U.S.Provisional Patent Applications: U.S. Provisional Application No.62/452,052 filed Jan. 30, 2017, and titled “Circuitry Housing Assembly”;U.S. Provisional Application No. 62/511,075 filed May 25, 2017, andtitled “Injectable Nerve-wrapping Electrode”; U.S. ProvisionalApplication No. 62/515,220 filed Jun. 5, 2017, and titled “ElongatedImplantable Devices”; U.S. Provisional Application No. 62/512,560 filedMay 30, 2017, and titled “Midfield Device Deployed in Arterial System”;U.S. Provisional Application No. 62/562,023 filed Sep. 22, 2017, andtitled “Midfield Device Deployable Inside Vasculature”; and U.S.Provisional Application No. 62/598,855, filed Dec. 14, 2017, and titled“Layered Midfield Transmitter with Dielectric Tuning”. The entirecontent of each of the identified U.S. provisional applications ishereby incorporated by reference herein.

TECHNICAL FIELD

One or more examples discussed herein regard devices, systems, andmethods for providing signals (e.g., wireless midfield signals) to animplantable device (e.g., stimulation device) using an external device(e.g., external midfield coupler or midfield power source). One or moreexamples discussed herein regard devices, systems, and methods forproviding therapy (e.g., stimulation or other modulation) or diagnosticsfrom an implantable device. One or more examples discussed herein regardconfigurations for the implantable device and the external device. Oneor more examples discussed herein regard communicating data from theimplantable device to the external device. One or more examplesdiscussed herein regard devices, systems, and methods for positioningthe implantable device at or near a specific location and/or shaping theimplantable device.

TECHNICAL BACKGROUND

Various wireless powering methods for implantable electronics are basedon nearfield or farfield coupling. These and other methods suffer fromseveral disadvantages. A power harvesting structure in an implanteddevice is typically large (e.g., typically on the order of a centimeteror larger). Coils external to the body in nearfield coupling cansimilarly be bulky and inflexible. Such constraints present difficultiesregarding incorporation of an external device into a patient's dailylife. Furthermore, the intrinsic exponential decay of nearfield signalslimits miniaturization of an implanted device beyond superficial depths(e.g., greater than 1 cm). On the other hand, the radiative nature offarfield signals can limit energy transfer efficiency.

Generally discussed herein are systems, devices, and methods forproviding or delivering a patient therapy using an implantable device.In an example, the patient therapy includes an electrostimulationtherapy provided to one or more neural targets in a patient body. In anexample, the electrostimulation therapy is provided using an implantabledevice that wirelessly receives power and data signals from a midfieldtransmitter.

Wireless midfield powering technology can be used to provide power froman external power source to an implanted electrostimulation device. Theexternal power source, or transmitter, can be located on or near atissue surface, such as at an external surface of a patient's skin.Midfield-based devices can have various advantages over conventionalimplantable devices. For example, midfield powering technology need notrequire a relatively large implanted pulse generator and one or moreleads that electrically connect the pulse generator to stimulationelectrodes. A midfield device can provide a simpler implant procedure,which can lead to a lower cost and a lower risk of infection or otherimplant complications.

Another advantage of using midfield powering technology includes abattery or power source that can be provided externally to the patient,and thus the low power consumption and high efficiency circuitrequirements of battery-powered implantable devices can be relaxed.Another advantage of using midfield powering technology can include animplanted device that can be physically smaller than a battery-powereddevice. Thus, midfield powering technology can help enable betterpatient tolerance and comfort along with potentially lower manufacturingand implantation costs.

There is a current unmet need that includes communicating power and/ordata using midfield transmitters and receivers, such as to communicatepower and/or data from an external midfield transmitter to or from animplanted device, such as a neural stimulation device or a sensordevice.

SUMMARY

Although considerable progress has been made in the realm of medicaldevice therapy, a need exists for therapy devices that providestimulation or other therapy to targeted locations within a body. A needfurther exists for efficient, wireless power and data communication withan implanted therapy delivery device and/or an implanted diagnostic(e.g., sensor) device.

In accordance with several embodiments, an implantable system caninclude an elongate structure configured for implantation in a patientbody using a catheter. The system can include an elongate circuit boardassembly including, in order along its lengthwise direction, a proximalportion, a first flexible portion, a central portion, a second flexibleportion, and a distal portion, and a hermetic enclosure configured toenclose the elongate circuit board assembly. In an example, the hermeticenclosure includes a first end cap with a conductive first feedthroughcoupled to a conductor on the proximal portion of the elongate circuitboard assembly, and a second end cap with a conductive secondfeedthrough coupled to a conductor on the distal portion of the elongatecircuit board assembly. In an example, the first and second flexibleportions have different length characteristics.

Various elongate midfield devices can be provided. In an example, suchan elongate device can include at least one antenna configured towirelessly receive power signals from an external device, a firstcircuitry housing including first circuitry therein coupled to theantenna, and a second circuitry housing including second circuitrytherein. The elongate device can include an elongated portion betweenthe first circuitry housing and the second circuitry housing, theelongated portion including one or more conductors extendingtherethrough and electrically coupling the first circuitry and thesecond circuitry. The elongate device can further include a body portioncoupled to the second circuitry housing, and one or more electrodesexposed on, or at least partially in, the body portion.

In an example, an electrode system can be deployable inside of a patientbody at a neural target using a cannula. Such an electrode system caninclude or use an elongated assembly body configured to houseelectrostimulation circuitry or sense circuitry, and an electrodeassembly coupled to the electrostimulation circuitry or sense circuitryand configured to provide electrostimulation to, or sense electricalsignal activity from, the neural target inside of the patient body. Inan example, the electrode assembly includes multiple elongate membersthat extend away from the assembly body in a predominately longitudinaldirection, and the electrode assembly can have a retracted firstconfiguration when the electrode assembly is inside of the cannula, andan expanded second configuration when the electrode assembly is outsideof the cannula. In an example, the electrode assembly has a furtherexpanded third configuration while the electrode assembly receives theneural target.

In an example, an electrostimulation and/or sensor system can beprovided for implantation inside of a blood vessel of a patient. Such asystem can include or use a wireless receiver circuit configured toreceive a wireless power and/or data signal from a source deviceexternal to the patient, and an expandable and contractible supportstructure having a first contracted configuration inside of a deliverycatheter and having a second expanded configuration outside of thedelivery catheter. In an example, the support structure is coupled tothe wireless receiver circuit.

In an example, a midfield transmitter can include a layered structure,such as can include at least a first conductive plane provided on afirst layer of the transmitter, one or more microstrips provided on asecond layer of the transmitter, and a third conductive plane providedon a third layer of the transmitter, the third conductive planeelectrically coupled to the first conductive plane using one or morevias that extend through the second layer. In an example, the midfieldtransmitter can include a first dielectric member interposed between thefirst and second conductive planes, and a different second dielectricmember interposed between the second and third conductive planes.

This Summary is intended to provide an overview of subject matter of thepresent application. It is not intended to provide an exclusive orexhaustive explanation of the invention or inventions discussed herein.The detailed description is included to provide further informationabout the present patent application.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

FIG. 1 illustrates generally a schematic of an embodiment of a systemusing wireless communication paths.

FIG. 2A illustrates generally a block diagram of an embodiment of amidfield source device.

FIG. 2B illustrates generally a block diagram of an embodiment of aportion of a system configured to receive a signal.

FIG. 3 illustrates generally a schematic view of an embodiment of amidfield antenna with multiple subwavelength structures.

FIG. 4 illustrates generally a diagram of an embodiment of aphase-matching and/or amplitude-matching network for a midfield sourcedevice.

FIG. 5 illustrates generally a diagram of an embodiment of circuitry ofan implantable device.

FIG. 6 illustrates generally a diagram of an embodiment of a firstimplantable device.

FIG. 7 illustrates generally a schematic view of an embodiment of acircuitry housing.

FIG. 8 illustrates generally a cross-section diagram of an embodiment ofa circuit board.

FIG. 9 illustrates generally a top view diagram of an embodiment of acircuit board.

FIG. 10 illustrates generally a top view diagram of an embodiment of acircuit board.

FIG. 11 illustrates generally an embodiment of a device that includesvarious electrical and/or electronic components coupled to a circuitboard.

FIG. 12 illustrates generally an embodiment of a device that includesvarious components coupled to a circuit board and the circuit boardcoupled to a first end cap.

FIG. 13 illustrates generally an embodiment of a device that includes acircuit board coupled to a first end cap and disposed in an enclosure.

FIG. 14 illustrates generally an embodiment of a device that includes acircuit board coupled to first and second end caps and disposed in anenclosure.

FIG. 15 illustrates generally an embodiment of a device that includes acircuit board coupled to first and second end caps and sealed inside anenclosure.

FIG. 16 illustrates generally an example of a top view of an end cap.

FIG. 17 illustrates generally an example of a cross-section view of theend cap from FIG. 16.

FIG. 18 illustrates generally an example of a cross-section view of anassembly that includes the end cap from FIG. 16 and a circuit board.

FIG. 19 illustrates generally an example of a top view of a dual-portcap.

FIG. 20 illustrates generally an example that includes a cross-sectionview of the dual-port cap from FIG. 19.

FIG. 21 illustrates generally an example of a top view of amultiple-port cap.

FIG. 22 illustrates generally an example that includes a cross-sectionview of the multiple-port cap from FIG. 21.

FIG. 23 illustrates generally an example that includes a side view ofthe multiple-port cap from FIG. 21.

FIG. 24 illustrates generally an example of a side view of an embodimentof an implantable device.

FIG. 25 illustrates generally an example of an elongated implantabledevice.

FIG. 26 illustrates generally an example of a system that includes theimplantable device from FIG. 25 implanted within tissue.

FIG. 27 illustrates generally a schematic example of first circuitrysuch as can be provided in a circuitry housing.

FIG. 28 illustrates generally a schematic example of second circuitrysuch as can be provided in a circuitry housing.

FIG. 29 illustrates generally an example of an elongated implantabledevice.

FIGS. 30A and 30B illustrate generally different views of an example ofan implantable electrode assembly inside of a cannula.

FIG. 30C illustrates generally an example of an implantable electrodeassembly partially outside of a cannula.

FIG. 30D illustrates generally an example of an implantable electrodeassembly deployed from a cannula and coupled to a push rod.

FIG. 30E illustrates generally an example of an implantable electrodeassembly including an intermediate lead.

FIG. 31A illustrates generally a first example of an implantableelectrode assembly approaching a neural target.

FIG. 31B illustrates generally a second example of an implantableelectrode assembly with nerve-wrapping electrodes flexing away from aneural target.

FIG. 31C illustrates generally a third example of an implantableelectrode assembly with nerve-wrapping electrodes provided about aneural target.

FIGS. 32A, 32B, and 32C illustrate generally examples of using aflexible electrode configuration to receive and retain a neural target.

FIGS. 33A and 33B illustrate generally side and perspective views,respectively, of a second implantable electrode assembly.

FIG. 34 illustrates generally an example that includes nerve-wrappingelectrodes and an electrode insulator member.

FIGS. 35A and 35B illustrate generally side and perspective views,respectively, of a third implantable electrode assembly.

FIG. 36 illustrates generally an example of an implantable electrode.

FIG. 37 illustrates generally an example of an implantable electrode.

FIG. 38 illustrates generally an example of an implantable electrodeassembly configured to deliver an electrostimulation axially to a neuraltarget.

FIG. 39 illustrates generally an example of an implantable electrodeassembly configured to deliver an electrostimulation transversely to aneural target.

FIG. 40 illustrates generally an example of an implantable electrodeassembly with a flexible body.

FIG. 41 illustrates generally an example of a method that includesaccessing a neural target and providing an electrode about the neuraltarget.

FIG. 42 illustrates generally an example of an implant location for amidfield device with respect to vasculature in the torso.

FIG. 43 illustrates generally an example that includes side andcross-section views of a midfield device configured for installation andfixation inside a blood vessel.

FIG. 44 illustrates generally a first example of a midfield device withmultiple passive elements that project laterally away from the midfielddevice's housing assembly.

FIG. 45 illustrates generally a second example of a midfield device withmultiple inflatable elements that project laterally away from themidfield device's housing assembly.

FIG. 46 illustrates generally a third example of a midfield device withmultiple active elements that project laterally away from the midfielddevice's housing assembly.

FIG. 47 illustrates generally a fourth example of a midfield device witha fixation element that projects laterally away from the midfielddevice's housing assembly.

FIG. 48 illustrates generally a variation of the example midfield devicefrom FIG. 43.

FIG. 49 illustrates generally an example of a stent-based system thatcan include a midfield device coupled to an expandable scaffold.

FIG. 50 illustrates generally an example of a stent-based orspring-based system that can include or use a midfield device.

FIG. 51 illustrates generally an example of a spring-based supportmember coupled to a midfield device.

FIG. 52 illustrates generally an example of a spring-based supportmember coupled to a midfield device.

FIG. 53 illustrates generally an example of a spring-based support thatincludes an elongate member having a coil shape.

FIG. 54 illustrates generally an example of a system that can includemultiple structures that are each configured for intravascular placementduring a single implant procedure.

FIG. 55 illustrates generally a cross section view of a lumen that canenclose an implantable midfield device, a deployment structure, and aninflatable balloon.

FIG. 56 illustrates generally a perspective view of an implantabledevice and deployment structure provided outside of a distal end of alumen.

FIG. 57 illustrates generally an example of an implantable deviceinstalled in a vessel.

FIG. 58 illustrates generally an example of an implantable device thatincludes a device housing and an antenna that can extend outside of thehousing.

FIG. 59 illustrates generally a perspective view of an example of afirst electrode assembly coupled to an electronics module for anintravascular implantable device.

FIG. 60 illustrates generally a perspective view of an example of asecond electrode assembly coupled to an electronics module for anintravascular implantable device.

FIG. 61 illustrates generally an example of an intravascular implantabledevice.

FIG. 62 illustrates generally a side view of an intravascularimplantable device.

FIG. 63 illustrates generally a perspective view of a secondintravascular implantable device.

FIG. 64 illustrates generally a perspective view of a thirdintravascular implantable device.

FIG. 65 illustrates generally an example of a midfield device coupled toan intravascular implantable device.

FIG. 66 illustrates generally an example of a midfield device coupled tothe intravascular implantable device inside of a vessel.

FIG. 67 illustrates generally a top view of an example of a first layerof a layered first transmitter.

FIG. 68A illustrates generally a top view of a second layer superimposedover a first layer of a layered first transmitter.

FIG. 68B illustrates generally a top view of a second layer superimposedover a different first layer of a layered transmitter.

FIG. 69 illustrates generally a perspective view of an example of thelayered first transmitter from FIGS. 67 and 68A.

FIG. 70 illustrates generally a side, cross-section view of the layeredfirst transmitter from FIGS. 67, 68A, and 69.

FIG. 71 illustrates generally a top view of an example of a layeredsecond transmitter.

FIG. 72 illustrates generally a perspective view of the layered secondtransmitter from FIG. 71.

FIG. 73 illustrates generally an example of a cross-section schematicfor a layered transmitter.

FIG. 74 illustrates generally an example that shows signal or fieldpenetration within tissue.

FIG. 75 illustrates generally an example that shows surface currentsthat result when a midfield transmitter is excited.

FIG. 76 illustrates generally an example of a chart that shows arelationship between coupling efficiency of transmitter ports to animplanted receiver with respect to a changing angle or rotation of theimplanted receiver.

FIGS. 77A, 77B, and 77C illustrate generally examples of differentpolarizations of a midfield transmitter.

FIG. 78 illustrates generally an example of a portion of a layeredmidfield transmitter showing a first layer with a slot.

FIG. 79 illustrates generally a perspective view of an example of alayered third transmitter.

FIG. 80 illustrates generally a side, cross-section view of the layeredthird transmitter from FIG. 79.

FIG. 81 illustrates a block diagram of an embodiment of a machine uponwhich one or more methods discussed herein can be performed or inconjunction with one or more systems or devices described herein may beused.

DETAILED DESCRIPTION

In the following description that includes examples of differentnerve-electrode interfaces, reference is made to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow, by way of illustration, specific embodiments in which theinvention can be practiced. These embodiments are also referred toherein as “examples.” Such examples can include elements in addition tothose shown or described. However, the present inventors alsocontemplate examples in which only those elements shown or described areprovided. The present inventors contemplate examples using anycombination or permutation of those elements shown or described (or oneor more aspects thereof), either with respect to a particular example(or one or more aspects thereof), or with respect to other examples (orone or more aspects thereof) shown or described herein. Generallydiscussed herein are implantable devices and methods of assembling theimplantable devices.

I. Implantable Systems and Devices

Section headings herein, like the one above (“IMPLANTABLE SYSTEMS ANDDEVICES”), are provided to guide a reader generally to materialcorresponding to the topic indicated by the heading. However,discussions under a particular heading are not to be construed asapplying only to configurations of a single type; instead, the variousfeatures discussed in the various sections or subsections herein can becombined in various ways and permutations. For example, some discussionof features and benefits of implantable systems and devices may be foundin the text and corresponding figures under the present section heading“IMPLANTABLE SYSTEMS AND DEVICES”.

Midfield powering technology can provide power to a deeply implantedelectrostimulation device from an external power source located on ornear a tissue surface, such as at an external surface of a user's skin.The user can be a clinical patient or other user. The midfield poweringtechnology can have one or more advantages over implantable pulsegenerators. For example, a pulse generator can have one or morerelatively large, implanted batteries and/or one or more lead systems.Midfield devices, in contrast, can include relatively small batterycells that can be configured to receive and store relatively smallamounts of power. A midfield device can include one or more electrodesintegrated in a unitary implantable package. Thus, in some examples, amidfield-powered device can provide a simpler implant procedure overother conventional devices, which can lead to a lower cost and a lowerrisk of infection or other implant complications. One or more of theadvantages can be from an amount of power transferred to the implanteddevice. The ability to focus the energy from the midfield device canallow for an increase in the amount of power transferred to theimplanted device.

An advantage of using midfield powering technology can include a mainbattery or power source being provided externally to the patient, andthus low power consumption and high efficiency circuitry requirements ofconventional battery-powered implantable devices can be relaxed. Anotheradvantage of using midfield powering technology can include an implanteddevice that can be physically smaller than a battery-powered device.Midfield powering technology can thus help enable better patienttolerance and comfort along with potentially lower costs to manufactureand/or to implant in patient tissue.

There is a current unmet need that includes communicating power and/ordata using midfield transmitters and receivers, such as to communicatepower and/or data from an external midfield coupler or source device toone or more implanted neural stimulation devices and/or one or moreimplanted sensor devices. The unmet need can further includecommunicating data from the one or more implanted neural stimulationdevices and implanted sensor devices to the external midfield coupler orsource device.

In one or more examples, multiple devices can be implanted in patienttissue and can be configured to deliver a therapy and/or sensephysiologic information about a patient and/or about the therapy. Themultiple implanted devices can be configured to communicate with one ormore external devices. In one or more examples, the one or more externaldevices are configured to provide power and/or data signals to themultiple implanted devices, such as concurrently or in atime-multiplexed (e.g., “round-robin”) fashion. The provided powerand/or data signals can be steered or directed by an external device totransfer the signals to an implant efficiently. Although the presentdisclosure may refer to a power signal or data signal specifically, suchreferences are to be generally understood as optionally including one orboth of power and data signals.

Several embodiments described herein can be advantageous because theyinclude one, several, or all of the following benefits: (i) a systemconfigured to (a) communicate power and/or data signals from a midfieldcoupler device to an implantable device via midfield radiofrequency (RF)signals, (b) generate and provide a therapy signal via one or moreelectrodes coupled to the implantable device, the therapy signalincluding an information component, and producing a signal incident toproviding the therapy signal, (c) receive a signal, based on the therapysignal, using electrodes coupled to the midfield coupler device, and (d)at the midfield coupler device or another device, decode and react tothe information component from the received signal; (ii) a dynamicallyconfigurable, active midfield transceiver that is configured to provideRF signals to modulate an evanescent field at a tissue surface andthereby generate a propagating field within tissue, such as to transmitpower and/or data signals to an implanted target device (see, e.g., theexample of FIG. 74 that shows signal penetration inside tissue); (iii)an implantable device including an antenna configured to receive amidfield power signal from the midfield transceiver and including atherapy delivery circuitry configured to provide signal pulses toelectrostimulation electrodes using a portion of the received midfieldpower signal, wherein the signal pulses include therapy pulses and datapulses, and the data pulses can be interleaved with or embedded in thetherapy pulses; (iv) an implantable device configured to encodeinformation, in a therapy signal, about the device itself, such asincluding information about the device's operating status, or about apreviously-provided, concurrent, or planned future therapy provided bythe device; (v) a midfield transceiver including electrodes that areconfigured to sense electrical signals at a tissue surface; and/or (vi)adjustable wireless signal sources and receivers that are configuredtogether to enable a communication loop or feedback loop.

In one or more examples, one or more of these benefits and others can berealized using a system for manipulating an evanescent field at or nearan external tissue surface to transmit power and/or data wirelessly toone or more target devices implanted in the tissue. In one or moreexamples, one or more of these benefits can be realized using a deviceor devices implanted in a body or capable of being implanted in a bodyand as described herein. In one or more examples, one or more of thesebenefits can be realized using a midfield powering and/or communicationdevice (e.g., a transmitter device and/or a receiver device or atransceiver device).

A system can include a signal generator system adapted to providemultiple different sets of signals (e.g., RF signals). Each set caninclude two or more separate signals in some embodiments. The system canalso include a midfield transmitter including multiple excitation ports,the midfield transmitter coupled to the RF signal generator system, andthe midfield transmitter being adapted to transmit the multipledifferent sets of RF signals at respective different times via theexcitation ports. The excitation ports can be adapted to receiverespective ones of the separate signals from each set of RF signals.Each of the transmitted sets of RF signals can include a non-negligiblemagnetic field (H-field) component that is substantially parallel to theexternal tissue surface. In one or more examples, each set oftransmitted RF signals is adapted or selected to differently manipulatean evanescent field at or near the tissue surface to transmit a powerand/or data signal to one or more target devices implanted in the tissuevia a midfield signal instead of via inductive nearfield coupling orradiative far-field transmission.

In one or more examples, one or more of the above-mentioned benefits,among others, can be realized, at least in part, using an implantabletherapy delivery device (e.g., a device configured to provide neuralstimulation) that includes receiver circuitry including an antenna(e.g., an electric-field or magnetic field based antenna) configured toreceive a midfield power signal from an external source device, such aswhen the receiver circuitry is implanted within tissue. The implantabletherapy delivery device can include therapy delivery circuitry. Thetherapy delivery circuitry can be coupled to the receiver circuitry. Thetherapy delivery circuitry can be configured to provide signal pulses toone or more energy delivery members (e.g., electrostimulationelectrodes), which may be integrally coupled to a body of the therapydelivery device or positioned separately from (e.g., not located on) thebody of the therapy delivery device), such as by using a portion of thereceived midfield power signal from the external source device (e.g.,sometimes referred to herein as an external device, an external source,an external midfield device, a midfield transmitter device, a midfieldcoupler, a midfield powering device, a powering device, or the like,depending on the configuration and/or usage context of the device). Thesignal pulses can include one or more electrostimulation therapy pulsesand/or data pulses. In one or more examples, one or more of theabove-mentioned benefits, among others, can be realized, at least inpart, using an external transmitter and/or receiver (e.g., transceiver)device that includes an electrode pair configured to be disposed at anexternal tissue surface, and the electrode pair is configured to receivean electrical signal via the tissue. The electrical signal cancorrespond to an electrostimulation therapy delivered to the tissue bythe therapy delivery device. A demodulator circuitry can be coupled tothe electrode pair and can be configured to demodulate a portion of thereceived electrical signal, such as to recover a data signal originatedby the therapy delivery device.

In one or more examples that include using a midfield wireless coupler,tissue can act as a dielectric to tunnel energy. Coherent interferenceof propagating modes can confine a field at a focal plane to less than acorresponding vacuum wavelength, for example, with a spot size subjectto a diffraction limit in a high-index material. In one or moreexamples, a receiver (e.g., implanted in tissue) positioned at such ahigh energy density region, can be one or more orders of magnitudesmaller than a conventional nearfield implantable receiver, or can beimplanted more deeply in tissue (e.g., greater than 1 cm in depth). Inone or more examples, a transmitter source described herein can beconfigured to provide electromagnetic energy to various targetlocations, including for example to one or more deeply implanteddevices. In an example, the energy can be provided to a location withgreater than about a few millimeters of positioning accuracy. That is, atransmitted power or energy signal can be directed or focused to atarget location that is within about one wavelength of the signal intissue. Such energy focusing is substantially more accurate than thefocusing available via traditional inductive means and is sufficient toprovide adequate power to a receiver on a millimeter scale. In otherwireless powering approaches using nearfield coupling (inductivecoupling and its resonant enhanced derivatives), evanescent componentsoutside tissue (e.g., near the source) remain evanescent inside tissue,which does not allow for effective depth penetration. Unlike nearfieldcoupling, energy from a midfield source is primarily carried inpropagating modes and, as a result, an energy transport depth is limitedby environmental losses rather than by intrinsic decay of the nearfield.Energy transfer implemented with these characteristics can be at leasttwo to three orders of magnitude more efficient than nearfield systems.

One or more of the systems, apparatuses, and methods discussed hereincan be used to help treat fecal or urinary incontinence (e.g.,overactive bladder), such as by stimulating the tibial nerve or anybranch of the tibial nerve, such as but not limited to the posteriortibial nerve, one or more nerves or nerve branches originating from thesacral plexus, including but not limited to S1-S4, the tibial nerve,and/or the pudendal nerve. Urinary incontinence may be treated bystimulating one or more of muscles of the pelvic floor, nervesinnervating the muscles of the pelvic floor, internal urethralsphincter, external urethral sphincter, and the pudendal nerve orbranches of the pudendal nerve.

One or more of the systems, apparatuses, and methods discussed hereincan be used to help treat sleep apnea and/or snoring by stimulating oneor more of a nerve or nerve branches of the hypoglossal nerve, the baseof the tongue (muscle), phrenic nerve(s), intercostal nerve(s),accessory nerve(s), and cervical nerves C3-C6. Treating sleep apneaand/or snoring can include providing energy to an implant to sense adecrease, impairment, or cessation of breathing (such as by measuringoxygen saturation).

One or more of the systems, apparatuses, and methods discussed hereincan be used to help treat vaginal dryness, such as by stimulating one ormore of Bartholin gland(s), Skene's gland(s), and inner wall of vagina.One or more of the systems, apparatuses, and methods discussed hereincan be used to help treat migraines or other headaches, such as bystimulating one or more of the occipital nerve, supraorbital nerve, C2cervical nerve, or branches thereof, and the frontal nerve, or branchesthereof. One or more of the systems, apparatuses, and methods discussedherein can be used to help treat post-traumatic stress disorder, hotflashes, and/or complex regional pain syndrome such as by stimulatingone or more of the stellate ganglion and the C4-C7 of the sympatheticchain.

One or more of the systems, apparatuses, and methods discussed hereincan be used to help treat neuralgia (e.g., trigeminal neuralgia), suchas by stimulating one or more of the sphenopalatine ganglion nerveblock, the trigeminal nerve, or branches of the trigeminal nerve. One ormore of the systems, apparatuses, and methods discussed herein can beused to help treat dry mouth (e.g., caused by side effects frommedications, chemotherapy or radiation therapy cancer treatments,Sjogren's disease, or by other cause of dry mouth), such as bystimulating one or more of Parotid glands, submandibular glands,sublingual glands, submucosa of the oral mucosa in the oral cavitywithin the tissue of the buccal, labial, and/or lingual mucosa, the softpalate, the lateral parts of the hard palate, and/or the floor of themouth and/or between muscle fibers of the tongue, Von Ebner glands,glossopharyngeal nerve (CN IX), including branches of CN IX, includingotic ganglion, a facial nerve (CN VII), including branches of CN VII,such as the submandibular ganglion, and branches of T1-T3, such as thesuperior cervical ganglion.

One or more of the systems, apparatuses, and methods discussed hereincan be used to help treat a transected nerve, such as by sensingelectrical output from the proximal portion of a transected nerve anddelivering electrical input into the distal portion of a transectednerve, and/or sensing electrical output from the distal portion of atransected nerve and delivering electrical input into the proximalportion of a transected nerve. One or more of the systems, apparatuses,and methods discussed herein can be used to help treat cerebral palsy,such as by stimulating one or more muscles or one or more nervesinnervation one or more muscles affected in a patient with cerebralpalsy. One or more of the systems, apparatuses, and methods discussedherein can be used to help treat erectile dysfunction, such as bystimulating one or more of pelvic splanchnic nerves (S2-S4) or anybranches thereof, the pudendal nerve, cavernous nerve(s), and inferiorhypogastric plexus.

One or more of the systems, apparatuses, and methods discussed hereincan be used to help treat menstrual pain, such as by stimulating one ormore of the uterus and the vagina. One or more of the systems,apparatuses, and methods discussed herein can be used as an intrauterinedevice, such as by sensing one or more PH and blood flow or deliveringcurrent or drugs to aid in contraception, fertility, bleeding, or pain.One or more of the systems, apparatuses, and methods discussed hereincan be used to incite human arousal, such as by stimulating femalegenitalia, including external and internal, including clitoris or othersensory active parts of the female, or by stimulating male genitalia.

One or more of the systems, apparatuses, and methods discussed hereincan be used to help treat hypertension, such as by stimulating one ormore of a carotid sinus, left or right cervical vagus nerve, or a branchof the vagus nerve. One or more of the systems, apparatuses, and methodsdiscussed herein can be used to help treat paroxysmal supraventriculartachycardia, such as by stimulating one or more of trigeminal nerve orbranches thereof, anterior ethmoidal nerve, and the vagus nerve. One ormore of the systems, apparatuses, and methods discussed herein can beused to help treat vocal cord dysfunction, such as by sensing theactivity of a vocal cord and the opposite vocal cord or just stimulatingone or more of the vocal cords by stimulating nerves innervating thevocal cord, the left and/or Right recurrent laryngeal nerve, and thevagus nerve.

One or more of the systems, apparatuses, and methods discussed hereincan be used to help repair tissue, such as by stimulating tissue to doone or more of enhancing microcirculation and protein synthesis to healwounds and restoring integrity of connective and/or dermal tissues. Oneor more of the systems, apparatuses, and methods discussed herein can beused to help asthma or chronic obstructive pulmonary disease, such as byone or more of stimulating the vagus nerve or a branch thereof, blockingthe release of norepinephrine and/or acetylcholine and/or interferingwith receptors for norepinephrine and/or acetylcholine.

One or more of the systems, apparatuses, and methods discussed hereincan be used to help treat cancer, such as by stimulating, to modulateone or more nerves near or in a tumor, such as to decrease thesympathetic innervation, such as epinephrine/NE release, and/orparasympathetic innervation, such as Ach. One or more of the systems,apparatuses, and methods discussed herein can be used to help treatdiabetes, such as by powering a sensor inside the human body thatdetects parameters of diabetes, such as a glucose level or ketone leveland using such sensor data to adjust delivery of exogenous insulin froman insulin pump. One or more of the systems, apparatuses, and methodsdiscussed herein can be used to help treat diabetes, such as by poweringa sensor inside the human body that detects parameters of diabetes, suchas a glucose level or ketone level, and using a midfield coupler tostimulate the release of insulin from islet beta cells.

One or more of the systems, apparatuses, and methods discussed hereincan be used to help treat neurological conditions, disorders or diseases(such as Parkinson's disease (e.g., by stimulating an internus ornucleus of the brain), Alzheimer's disease, Huntington's disease,dementia, Creutzfeldt-Jakob disease, epilepsy (e.g., by stimulating aleft cervical vagus nerve or a trigeminal nerve), post-traumatic stressdisorder (PTSD) (e.g., by stimulating a left cervical vagus nerve), oressential tremor, such as by stimulating a thalamus), neuralgia,depression, dystonia (e.g., by stimulating an internus or nucleus of thebrain), phantom limb (e.g., by stimulating an amputated nerve, such anending of an amputated nerve), dry eyes (e.g., by stimulating a lacrimalgland), arrhythmia (e.g., by stimulating the heart), a gastrointestinaldisorder, such as obesity, gastroesophageal reflux, and/orgastroparesis, such as by stimulating a C1-C2 occipital nerve or deepbrain stimulation (DB S) of the hypothalamus, an esophagus, a musclenear sphincter leading to the stomach, and/or a lower stomach, and/orstroke (e.g., by subdural stimulation of a motor cortex). Using one ormore examples discussed herein, stimulation can be providedcontinuously, on demand (e.g., as demanded by a physician, patient, orother user), or periodically.

In providing the stimulation, an implantable device can be situated upto five centimeters or more below the surface of the skin. A midfieldpowering device is capable of delivering power to those depths intissue. In one or more examples, an implantable device can be situatedbetween about 2 centimeters and 4 centimeters, about 3 centimeters,between about 1 centimeter and five centimeters, less than 1 centimeter,about two centimeters, or other distance below the surface of the skin.The depth of implantation can depend on the use of the implanted device.For example, to treat depression, hypertension, epilepsy, and/or PTSDthe implantable device can situated between about 2 centimeters andabout four centimeters below the surface of the skin. In anotherexample, to treat sleep apnea, arrhythmia (e.g., bradycardia), obesity,gastroesophageal reflux, and/or gastroparesis the implantable device canbe situated at greater than about 3 centimeters below the surface of theskin. In yet another example, to treat Parkinson's, essential tremors,and/or dystonia the implantable device can be situated between about 1centimeter and about 5 centimeters below the surface of the skin. Yetother examples include situating the implantable device between about 1centimeter and about 2 centimeters below the surface of the skin, suchas to treat fibromyalgia, stroke, and/or migraine, at about 2centimeters to treat asthma, and at about one centimeter or less totreat dry eyes.

Although many embodiments included herein describe devices or methodsfor providing stimulation (e.g., electrostimulation), the embodimentsmay be adapted to provide other forms of modulation (e.g., denervation)in addition to or instead of stimulation. In addition, although manyembodiments included herein refer to the use of electrodes to delivertherapy, other energy delivery members (e.g., ultrasound transducers orother ultrasound energy delivery members) or other therapeutic membersor substances (e.g., fluid delivery devices or members to deliverchemicals, drugs, cryogenic fluid, hot fluid or steam, or other fluids)may be used or delivered in other embodiments.

FIG. 1 illustrates generally a schematic of an embodiment of a system100 using wireless communication paths. The system 100 includes anexample of an external source 102, such as a midfield transmittersource, sometimes referred to as a midfield coupler, located at or abovean interface 105 between air 104 and a higher-index material 106, suchas body tissue. The external source 102 can produce a source current(e.g., an in-plane source current). The source current (e.g., in-planesource current) can generate an electric field and a magnetic field. Themagnetic field can include a non-negligible component that is parallelto the surface of the source 102 and/or to a surface of the higher-indexmaterial 106 (e.g., a surface of the higher-index material 106 thatfaces the external source 102). In accordance with several embodiments,the external source 102 may comprise structural features and functionsdescribed in connection with the midfield couplers and external sourcesincluded in WIPO Publication No. WO/2015/179225 published on Nov. 26,2015 and titled “MIDFIELD COUPLER”, which is incorporated herein byreference in its entirety.

The external source 102 can include at least a pair of outwardly facingelectrodes 121 and 122. The electrodes 121 and 122 can be configured tocontact a tissue surface, for example, at the interface 105. In one ormore examples, the external source 102 is configured for use with asleeve, pocket, or other garment or accessory that maintains theexternal source 102 adjacent to the higher-index material 106, and thatoptionally maintains the electrodes 121 and 122 in physical contact witha tissue surface. In one or more examples, the sleeve, pocket, or othergarment or accessory can include or use a conductive fiber or fabric,and the electrodes 121 and 122 can be in physical contact with thetissue surface via the conductive fiber or fabric.

In one or more examples, more than two outwardly facing electrodes canbe used and processor circuitry on-board or auxiliary to the source 102can be configured to select an optimal pair or group of electrodes touse to sense farfield signal information (e.g., signal informationcorresponding to a delivered therapy signal or to a nearfield signal).In such embodiments, the electrodes can operate as antennas. In one ormore examples, the source 102 includes three outwardly facing electrodesarranged as a triangle, or four outwardly facing electrodes arranged asa rectangle, and any two or more of the electrodes can be selected forsensing and/or can be electrically grouped or coupled together forsensing or diagnostics. In one or more examples, the processor circuitrycan be configured to test multiple different electrode combinationselections to identify an optimal configuration for sensing a farfieldsignal (an example of the processor circuitry is presented in FIG. 2A,among others).

FIG. 1 illustrates an embodiment of an implantable device 110, such ascan include a multi-polar therapy delivery device configured to beimplanted in the higher-index material 106 or in a blood vessel. In oneor more examples, the implantable device 110 includes all or a portionof the circuitry 500 from FIG. 5, discussed in further detail below. Inone or more examples, the implantable device 110 is implanted in tissuebelow the tissue-air interface 105. In FIG. 1, the implantable device110 includes an elongate body and multiple electrodes E0, E1, E2, and E3that are axially spaced apart along a portion of the elongate body. Theimplantable device 110 includes receiver and/or transmitter circuitry(not shown in FIG. 1, see e.g., FIGS. 2A, 2B, and 4, among others) thatcan enable communication between the implantable device 110 and theexternal source 102.

The various electrodes E0-E3 can be configured to deliverelectrostimulation therapy to patient tissue, such as at or near aneural or muscle target. In one or more examples, at least one electrodecan be selected for use as an anode and at least one other electrode canbe selected for use as a cathode to define an electrostimulation vector.In one or more examples, electrode E1 is selected for use as an anodeand electrode E2 is selected for use as a cathode. Together, the E1-E2combination defines an electrostimulation vector V12. Various vectorscan be configured independently to provide a neural electrostimulationtherapy to the same or different tissue target, such as concurrently orat different times.

In one or more examples, the source 102 includes an antenna (see, e.g.,FIG. 3) and the implantable device 110 includes an antenna 108 (e.g.,and electric field-based or magnetic field-based antenna). The antennascan be configured (e.g., in length, width, shape, material, etc.) totransmit and receive signals at substantially the same frequency. Theimplantable device 110 can be configured to transmit power and/or datasignals through the antenna 108 to the external source 102 and canreceive power and/or data signals transmitted by the external source102. The external source 102 and implantable device 110 can be used fortransmission and/or reception of RF signals. A transmit/receive (T/R)switch can be used to switch each RF port of the external source 102from a transmit (transmit data or power) mode to a receive (receivedata) mode. A T/R switch can similarly be used to switch the implantabledevice 110 between transmit and receive modes. See FIG. 4, among others,for examples of T/R switches.

In one or more examples, a receive terminal on the external source 102can be connected to one or more components that detect a phase and/oramplitude of a received signal from the implantable device 110. Thephase and amplitude information can be used to program a phase of thetransmit signal, such as to be substantially the same relative phase asa signal received from the implantable device 110. To help achieve this,the external source 102 can include or use a phase-matching and/oramplitude-matching network, such as shown in the embodiment of FIG. 4.The phase-matching and/or amplitude matching network can be configuredfor use with a midfield antenna that includes multiple ports, such asshown in the embodiment of FIG. 3.

Referring again to FIG. 1, in one or more examples, the implantabledevice 110 can be configured to receive a midfield signal 131 from theexternal source 102. The midfield signal 131 can include power and/ordata signal components. In some embodiments, a power signal componentcan include one or more data components embedded therein. In one or moreexamples, the midfield signal 131 includes configuration data for use bythe implantable device 110. The configuration data can define, amongother things, therapy signal parameters, such as a therapy signalfrequency, pulse width, amplitude, or other signal waveform parameters.In one or more examples, the implantable device 110 can be configured todeliver an electrostimulation therapy to a therapy target 190, such ascan include a neural target (e.g., a nerve, or other tissue such as avein, connective tissue, or other tissue that includes one or moreneurons within or near the tissue), a muscle target, or other tissuetarget. An electrostimulation therapy delivered to the therapy target190 can be provided using a portion of a power signal received from theexternal source 102. Examples of the therapy target 190 can includenerve tissue or neural targets, for example including nerve tissue orneural targets at or near cervical, thoracic, lumbar, or sacral regionsof the spine, brain tissue, muscle tissue, abnormal tissue (e.g., tumoror cancerous tissue), targets corresponding to sympathetic orparasympathetic nerve systems, targets at or near peripheral nervebundles or fibers, at or near other targets selected to treatincontinence, urinary urge, overactive bladder, fecal incontinence,constipation, pain, neuralgia, pelvic pain, movement disorders or otherdiseases or disorders, deep brain stimulation (DBS) therapy targets orany other condition, disease or disorder (such as those otherconditions, diseases, or disorders identified herein).

Delivering the electrostimulation therapy can include using a portion ofa power signal received via the midfield signal 131, and providing acurrent signal to an electrode or an electrode pair (e.g., two or moreof E0-E3), coupled to the implantable device 110, to stimulate thetherapy target 190. As a result of the current signal provided to theelectrode(s), a nearfield signal 132 can be generated. An electricpotential difference resulting from the nearfield signal 132 can bedetected remotely from the therapy delivery location. Various factorscan influence where and whether the potential difference can bedetected, including, among other things, characteristics of the therapysignal, a type or arrangement of the therapy delivery electrodes, andcharacteristics of any surrounding biologic tissue. Such a remotelydetected electric potential difference can be considered a farfieldsignal 133. The farfield signal 133 can represent an attenuated portionof the nearfield signal 132. That is, the nearfield signal 132 and thefarfield signal 133 can originate from the same signal or field, such aswith the nearfield signal 132 considered to be associated with a regionat or near the implantable device 110 and the therapy target 190, andwith the farfield signal 133 considered to be associated with otherregions more distal from the implantable device 110 and the therapytarget 190. In one or more examples, information about the implantabledevice 110, or about a previously-provided or future planned therapyprovided by the implantable device 110, can be encoded in a therapysignal and detected and decoded by the external source 102 by way of thefarfield signal 133.

In one or more examples, the device 110 can be configured to provide aseries of electrostimulation pulses to a tissue target (e.g., neuraltarget). For example, the device 110 can provide multipleelectrostimulation pulses separated in time, such as using the same ordifferent electrostimulation vectors, to provide a therapy. In one ormore examples, a therapy comprising multiple signals can be provided tomultiple different vectors in parallel, or can be provided in sequencesuch as to provide a series or sequence of electrostimulation pulses tothe same neural target. Thus, even if one vector is more optimal thanthe others for eliciting a patient response, the therapy as a whole canbe more effective than stimulating only the known-optimal vector because(1) the target may experience a rest period during periods ofnon-stimulation, and/or (2) stimulating the areas nearby and/or adjacentto the optimal target can elicit some patient benefit.

The system 100 can include a sensor 107 at or near the interface 105between air 104 and the higher-index material 106. The sensor 107 caninclude, among other things, one or more electrodes, an optical sensor,an accelerometer, a temperature sensor, a force sensor, a pressuresensor, or a surface electromyography (EMG) device. The sensor 107 maycomprise multiple sensors (e.g., two, three, four or more than foursensors). Depending on the type of sensor(s) used, the sensor 107 can beconfigured to monitor electrical, muscle, or other activity near thedevice 110 and/or near the source 102. For example, the sensor 107 canbe configured to monitor muscle activity at a tissue surface. If muscleactivity greater than a specified threshold activity level is detected,then a power level of the source 102 and/or of the device 110 can beadjusted. In one or more examples, the sensor 107 can be coupled to orintegrated with the source 102, and in other examples, the sensor 107can be separate from, and in data communication with (e.g., using awired or wireless electrical coupling or connection), the source 102and/or the device 110.

The system 100 can include a farfield sensor device 130 that can beseparate from, or communicatively coupled with, one or more of thesource 102 and the sensor 107. The farfield sensor device 130 caninclude two or more electrodes and can be configured to sense a farfieldsignal, such as the farfield signal 133 corresponding to a therapydelivered by the device 110. The farfield sensor device 130 can includeat least one pair of outwardly facing electrodes 123 and 124 configuredto contact a tissue surface, for example, at the interface 105. In oneor more examples, three or more electrodes can be used, and processorcircuitry on-board or auxiliary to the farfield sensor device 130 canselect various combinations of two or more of the electrodes for use insensing the farfield signal 133. In one or more examples, the farfieldsensor device 130 can be configured for use with a sleeve, pocket, orother garment or accessory that maintains the farfield sensor device 130adjacent to the higher-index material 106, and that optionally maintainsthe electrodes 123 and 124 in physical contact with a tissue surface. Inone or more examples, the sleeve, pocket, or other garment or accessorycan include or use a conductive fiber or fabric, and the electrodes 123and 124 can be in physical contact with the tissue surface via theconductive fiber or fabric. An example of at least a portion of afarfield sensor device 130 is further described herein in connectionwith FIG. 2B.

In one or more examples, the external source 102 provides a midfieldsignal 131 including power and/or data signals to the implantable device110. The midfield signal 131 includes a signal (e.g., an RF signal)having various or adjustable amplitude, frequency, phase, and/or othersignal characteristics. The implantable device 110 can include anantenna, such as described below, that can receive the midfield signal131 and, based on characteristics of receiver circuitry in theimplantable device 110, can modulate the received signal at the antennato thereby generate a backscatter signal. In one or more examples, theimplantable device 110 can encode information in the backscatter signal112, such as information about a characteristic of the implantabledevice 110 itself, about a received portion of the midfield signal 131,about a therapy provided by the implantable device 110, and/or otherinformation. The backscatter signal 112 can be received by an antenna atthe external source 102 and/or the farfield sensor device 130, or can bereceived by another device. In one or more examples, a biological signalcan be sensed by a sensor of the implantable device 110, such as aglucose sensor, an electropotential (e.g., an electromyography sensor,electrocardiograph (ECG) sensor, resistance, or other electricalsensor), a light sensor, a temperature, a pressure sensor, an oxygensensor, a motion sensor, or the like. A signal representative of thedetected biological signal can be modulated onto the backscatter signal112. Other sensors are discussed elsewhere herein, such as with regardto FIG. 81, among others. In such embodiments, the sensor 107 caninclude a corresponding monitor device, such as a glucose, temperature,ECG, EMG, oxygen, or other monitor, such as to receive, demodulate,interpret, and/or store data modulated onto the backscatter signal.

In one or more examples, the external source 102 and/or the implantabledevice 110 can include an optical transceiver configured to facilitatecommunication between the external source 102 and the implantable device110. The external source 102 can include a light source, such as a photolaser diode or LED, or can include a photo detector, or can include bothof a light source and a photo detector. The implantable device 110 caninclude a light source, such as a photo laser diode or LED, or caninclude a photo detector, or can include both of a light source and aphoto detector. In an example, the external source 102 and/orimplantable device 110 can include a window, such as made of quartz,glass, or other translucent material, adjacent to its light source orphoto detector.

In an example, optical communications can be separate from orsupplemental to an electromagnetic coupling between the external source102 and the implantable device 110. Optical communication can beprovided using light pulses modulated according to various protocols,such as using pulse position modulation (PPM). In an example, a lightsource and/or photo detector on-board the implantable device 110 can bepowered by a power signal received at least in part via midfieldcoupling with the external source 102.

In an example, a light source at the external source 102 can send acommunication signal through skin, into subcutaneous tissue, and throughan optical window (e.g., quartz window) in the implantable device 110.The communication signal can be received at a photo detector on-boardthe implantable device 110. Various measurement information, therapyinformation, or other information from or about the implantable devicecan be encoded and transmitted from the implantable device 110 using alight source provided at the implantable device 110. The light signalemitted from the implantable device 110 can travel through the sameoptical window, subcutaneous tissue, and skin tissue, and can bereceived at photo detector on-board the external source 102. In anexample, the light sources and/or photo detectors can be configured toemit and/or receive, respectively, electromagnetic waves in the visibleor infrared ranges, such as in a range of about 670-910 nm wavelength(e.g., 670 nm-800 nm, 700 nm-760 nm, 670 nm-870 nm, 740 nm-850 nm, 800nm-910 nm, overlapping ranges thereof, or any value within the recitedranges).

FIG. 2A illustrates, by way of example, a block diagram of andembodiment of a midfield source device, such as the external source 102.The external source 102 can include various components, circuitry, orfunctional elements that are in data communication with one another. Inthe example of FIG. 2A, the external source 102 includes components,such as processor circuitry 210, one or more sensing electrodes 220(e.g., including the electrodes 121 and 122), a demodulator circuitry230, a phase-matching or amplitude-matching network 400, a midfieldantenna 300, and/or one or more feedback devices, such as can include oruse an audio speaker 251, a display interface 252, and/or a hapticfeedback device 253. The midfield antenna 300 is further described belowin the embodiment of FIG. 3, and the network 400 is further describedbelow in the embodiment of FIG. 4. The processor circuitry 210 can beconfigured to coordinate the various functions and activities of thecomponents, circuitry, and/or functional elements of the external source102.

The midfield antenna 300 can be configured to provide a midfieldexcitation signal, such as can include RF signals having anon-negligible H-field component that is substantially parallel to anexternal tissue surface. In one or more examples, the RF signals can beadapted or selected to manipulate an evanescent field at or near atissue surface, such as to transmit a power and/or data signal torespective different target devices (e.g., the implantable device 110,or any one or more other implantable devices discussed herein) implantedin tissue. The midfield antenna 300 can be further configured to receivebackscatter or other wireless signal information that can be demodulatedby the demodulator circuitry 230. The demodulated signals can beinterpreted by the processor circuitry 210. The midfield antenna 300 caninclude a dipole antenna, a loop antenna, a coil antenna, a slot orstrip antenna, or other antenna. The antenna 300 can be shaped and sizedto receive signals in a range of between about 400 MHz and about 4 GHz(e.g., between 400 MHz and 1 GHz, between 400 MHz and 3 GHz, between 500MHz and 2 GHz, between 1 GHz and 3 GHz, between 500 MHz and 1.5 GHz,between 1 GHz and 2 GHz, between 2 GHz and 3 GHz, overlapping rangesthereof, or any value within the recited ranges). For embodimentsincorporating a dipole antenna, the midfield antenna 300 may comprise astraight dipole with two substantially straight conductors, a foldeddipole, a short dipole, a cage dipole, a bow-tie dipole or batwingdipole.

The demodulator circuitry 230 can be coupled to the sensing electrodes220. In one or more examples, the sensing electrodes 220 can beconfigured to receive the farfield signal 133, such as based on atherapy provided by the implantable device 110, such as can be deliveredto the therapy target 190. The therapy can include an embedded orintermittent data signal component that can be extracted from thefarfield signal 133 by the demodulator circuitry 230. For example, thedata signal component can include an amplitude-modulated orphase-modulated signal component that can be discerned from backgroundnoise or other signals and processed by the demodulator circuitry 230 toyield an information signal that can be interpreted by the processorcircuitry 210. Based on the content of the information signal, theprocessor circuitry 210 can instruct one of the feedback devices toalert a patient, caregiver, or other system or individual. For example,in response to the information signal indicating successful delivery ofa specified therapy, the processor circuitry 210 can instruct the audiospeaker 251 to provide audible feedback to a patient, can instruct thedisplay interface 252 to provide visual or graphical information to apatient, and/or can instruct the haptic feedback device 253 to provide ahaptic stimulus to a patient. In one or more examples, the hapticfeedback device 253 includes a transducer configured to vibrate or toprovide another mechanical signal.

FIG. 2B illustrates generally a block diagram of a portion of a systemconfigured to receive a farfield signal. The system can include thesensing electrodes 220, such as can include the electrodes 121 and 122of the source 102, or the electrodes 123 and 124 of the farfield sensordevice 130. In the example of FIG. 2B, there are at least four sensingelectrodes represented collectively as the sensing electrodes 220, andindividually as SE0, SE1, SE2, and SE3; however, other numbers ofsensing electrodes 220 may also be used. The sensing electrodes can becommunicatively coupled to multiplexer circuitry 261. The multiplexercircuitry 261 can select pairs of the electrodes, or electrode groups,for use in sensing farfield signal information. In one or more examples,the multiplexer circuitry 261 selects an electrode pair or groupingbased on a detected highest signal to noise ratio of a received signal,or based on another relative indicator of signal quality, such asamplitude, frequency content, and/or other signal characteristic.

Sensed electrical signals from the multiplexer circuitry 261 can undergovarious processing to extract information from the signals. For example,analog signals from the multiplexer circuitry 261 can be filtered by aband pass filter 262. The band pass filter 262 can be centered on aknown or expected modulation frequency of a sensed signal of interest. Aband pass filtered signal can then be amplified by a low-noise amplifier263. The amplified signal can be converted to a digital signal by ananalog-to-digital converter circuitry (ADC) 264. The digital signal canbe further processed by various digital signal processors 265, asfurther described herein, such as to retrieve or extract an informationsignal communicated by the implantable device 110.

FIG. 3 illustrates generally a schematic view of an embodiment of amidfield antenna 300 with multiple subwavelength structures 301, 302,303, and 304. The midfield antenna 300 can include a midfield platestructure with a planar surface. The one or more subwavelengthstructures 301-304 can be formed in the plate structure. In the exampleof FIG. 3, the antenna 300 includes a first subwavelength structure 301,a second subwavelength structure 302, a third subwavelength structure303, and a fourth subwavelength structure 304. Fewer or additionalsubwavelength structures can be used. The subwavelength structures canbe excited individually or selectively by one or more RF ports (e.g.,first through fourth RF ports 311, 312, 313, and 314) respectivelycoupled thereto. A “subwavelength structure” can include a hardwarestructure with dimensions defined relative to a wavelength of a fieldthat is rendered and/or received by the external source 102. Forexample, for a given λ₀ corresponding to a signal wavelength in air, asource structure that includes one or more dimensions less than λ₀ canbe considered to be a subwavelength structure. Various designs orconfigurations of subwavelength structures can be used. Some examples ofa subwavelength structure can include a slot in a planar structure, or astrip or patch of a conductive sheet of substantially planar material.

FIG. 4 illustrates generally the phase-matching or amplitude-matchingnetwork 400. In an example, the network 400 can include the antenna 300,and the antenna 300 can be electrically coupled to a plurality ofswitches 404A, 404B, 404C, and 404D, for example, via the first throughfourth RF ports 311, 312, 313, and 314 illustrated in FIG. 3. Theswitches 404A-D are each electrically coupled to a respective phaseand/or amplitude detector 406A, 406B, 406C, and 406D, and a respectivevariable gain amplifier 408A, 408B, 408C, and 408D. Each amplifier408A-D is electrically coupled to a respective phase shifter 410A, 410B,410C, and 410D, and each phase shifter 410A-D is electrically coupled toa common power divider 412 that receives an RF input signal 414 to betransmitted using the external source 102.

In one or more examples, the switches 404A-D can be configured to selecteither a receive line (“R”) or a transmit line (“T”). A number ofswitches 404A-D of the network 400 can be equal to a number of ports ofthe midfield source 402. In the example of the network 400, the midfieldsource 402 includes four ports (e.g., corresponding to the foursubwavelength structures in the antenna 300 of the example of FIG. 3),however any number of ports (and switches), such as one, two, three,four, five, six, seven, eight or more, can be used.

The phase and/or amplitude detectors 406A-D are configured to detect aphase (Φ1, Φ2, Φ3, Φ4) and/or power (P1, P2, P3, P4) of a signalreceived at each respective port of the midfield source 402. In one ormore examples, the phase and/or amplitude detectors 406A-D can beimplemented in one or more modules (hardware modules that can includeelectric or electronic components arranged to perform an operation, suchas determining a phase or amplitude of a signal), such as including aphase detector module and/or an amplitude detector module. The detectors406A-D can include analog and/or digital components arranged to produceone or more signals representative of a phase and/or amplitude of asignal received at the external source 102.

The amplifiers 408A-D can receive respective inputs from the phaseshifters 410A-D (e.g., Pk phase shifted by Φk, Φ1+Φk, Φ2+Φk, Φ3+Φk, orΦ4+Φk). The output of the amplifier, O, is generally the output of thepower divider, M when the RF signal 414 has an amplitude of 4*M (in theembodiment of FIG. 4), multiplied by the gain of the amplifier Pi*Pk. Pkcan be set dynamically as the values for P1, P2, P3, and/or P4 change.Φk can be a constant. In one or more examples, the phase shifters 410A-Dcan dynamically or responsively configure the relative phases of theports based on phase information received from the detectors 406A-D.

In one or more examples, a transmit power requirement from the midfieldsource 402 is Ptt. The RF signal provided to the power divider 412 has apower of 4*M. The output of the amplifier 408A is about M*P1*Pk. Thus,the power transmitted from the midfield coupler isM*(P1*Pk+P2*Pk+P3*Pk+P4*Pk)=Ptt. Solving for Pk yieldsPk=Ptt/(M*(P1+P2+P3+P4)).

The amplitude of a signal at each RF port can be transmitted with thesame relative (scaled) amplitude as the signal received at therespective port of the midfield coupler coupled thereto. The gain of theamplifiers 408A-D can be further refined to account for any lossesbetween the transmission and reception of the signal from the midfieldcoupler. Consider a reception efficiency of η=Pir/Ptt, where Pir is thepower received at the implanted receiver. An efficiency (e.g., a maximumefficiency), given a specified phase and amplitude tuning, can beestimated from an amplitude received at the external midfield sourcefrom the implantable source. This estimation can be given asη≈(P1+P2+P3+P4)/Pit, where Pit is an original power of a signal from theimplanted source. Information about a magnitude of the power transmittedfrom the implantable device 110 can be communicated as a data signal tothe external source 102. In one or more examples, an amplitude of asignal received at an amplifier 408A-D can be scaled according to thedetermined efficiency, such as to ensure that the implantable devicereceives power to perform one or more programmed operation(s). Given theestimated link efficiency, η, and an implant power (e.g., amplitude)requirement of Pir′, Pk can be scaled as Pk=Pir′/[q(P1+P2+P3+P4)], suchas to help ensure that the implant receives adequate power to performthe programmed functions.

Control signals for the phase shifters 410A-D and the amplifiers 408A-D,such as the phase input and gain input, respectively, can be provided byprocessing circuitry that is not shown in FIG. 4. The circuitry isomitted to not overly complicate or obscure the view provided in FIG. 4.The same or different processing circuitry can be used to update astatus of one or more of the switches 404A-D between receive andtransmit configurations. See the processor circuitry 210 of FIG. 2A andits associated description for an example of processing circuitry.

FIG. 5 illustrates generally a diagram of an embodiment of circuitry 500of the implantable device 110, or target device, such as can include anelongate device and such as can optionally be deployed inside a bloodvessel, according to one or more of the embodiments discussed herein.The circuitry 500 includes one or more pad(s) 536, such as can beelectrically connected to the antenna 108. The circuitry 500 can includea tunable matching network 538 to set an impedance of the antenna 108based on an input impedance of the circuitry 500. The impedance of theantenna 108 can change, for example, due to environmental changes. Thetunable matching network 538 can adjust the input impedance of thecircuitry 500 based on the varying impedance of the antenna 108. In oneor more examples, the impedance of the tunable matching network 538 canbe matched to the impedance of the antenna 108. In one or more examples,the impedance of the tunable matching network 538 can be set to cause aportion of a signal incident on the antenna 108 reflect back from theantenna 108, thus creating a backscatter signal.

A transmit-receive (T/R) switch 541 can be used to switch the circuitry500 from a receive mode (e.g., in which power and/or data signals can bereceived) to a transmit mode (e.g., in which signals can be transmittedto another device, implanted or external). An active transmitter canoperate at an Industrial, Scientific, and Medical (ISM) band of 2.45 GHZor 915 MHz, or the 402 MHz Medical Implant Communication Service (MICS)band for transferring data from the implant. Alternatively, data can betransmitted using a Surface Acoustic Wave (SAW) device that backscattersincident radio frequency (RF) energy to the external device.

The circuitry 500 can include a power meter 542 for detecting an amountof received power at the implanted device. A signal that indicates powerfrom the power meter 542 can be used by a digital controller 548 todetermine whether received power is adequate (e.g., above a specifiedthreshold) for the circuitry to perform some specified function. Arelative value of a signal produced by the power meter 542 can be usedto indicate to a user or machine whether an external device (e.g., thesource 102) used to power the circuitry 500 is in a suitable locationfor transferring power and/or data to the target device.

In one or more examples, the circuitry 500 can include a demodulator 544for demodulating received data signals. Demodulation can includeextracting an original information-bearing signal from a modulatedcarrier signal. In one or more examples, the circuitry 500 can include arectifier 546 for rectifying a received AC power signal.

Circuitry (e.g., state logic, Boolean logic, or the like) can beintegrated into the digital controller 548. The digital controller 548can be configured to control various functions of the receiver device,such as based on the input(s) from one or more of the power meter 542,demodulator 544, and/or the clock 550. In one or more examples, thedigital controller 548 can control which electrode(s) (e.g., E0-E3) areconfigured as a current sink (anode) and which electrode(s) areconfigured as a current source (cathode). In one or more examples, thedigital controller 548 can control a magnitude of a stimulation pulseproduced through the electrode(s).

A charge pump 552 can be used to increase the rectified voltage to ahigher voltage level, such as can be suitable for stimulation of thenervous system. The charge pump 552 can use one or more discretecomponents to store charge for increasing the rectified voltage. In oneor more examples, the discrete components include one or morecapacitors, such as can be coupled to pad(s) 554. In one or moreexamples, these capacitors can be used for charge balancing duringstimulation, such as to help avoid tissue damage.

A stimulation driver circuitry 556 can provide programmable stimulationthrough various outputs 534, such as to an electrode array. Thestimulation driver circuitry 556 can include an impedance measurementcircuitry, such as can be used to test for correct positioning of theelectrode(s) of the array. The stimulation driver circuitry 556 can beprogrammed by the digital controller to make an electrode a currentsource, a current sink, or a shorted signal path. The stimulation drivercircuitry 556 can be a voltage or a current driver. The stimulationdriver circuitry 556 can include or use a therapy delivery circuitrythat is configured to provide electrostimulation signal pulses to one ormore electrodes, such as using at least a portion of a received midfieldpower signal from the external source 102. In one or more examples, thestimulation driver circuitry 556 can provide pulses at frequencies up toabout 100 kHz. Pulses at frequencies around 100 kHz can be useful fornerve blocking.

The circuitry 500 can further include a memory circuitry 558, such ascan include a non-volatile memory circuitry. The memory circuitry 558can include storage of a device identification, neural recordings,and/or programming parameters, among other implant related data.

The circuitry 500 can include an amplifier 555 and analog digitalconverter (ADC) 557 to receive signals from the electrode(s). Theelectrode(s) can sense electricity from nerve signals within the body.The nerve signals can be amplified by the amplifier 555. These amplifiedsignals can be converted to digital signals by the ADC 557. Thesedigital signals can be communicated to an external device. The amplifier555, in one or more examples, can be a trans-impedance amplifier.

The digital controller 548 can provide data to a modulator/poweramplifier 562. The modulator/power amplifier 562 modulates the data ontoa carrier wave. The power amplifier 562 increases the magnitude of themodulated waveform to be transmitted.

The modulator/power amplifier 562 can be driven by an oscillator/phaselocked loop (PLL) 560. The PLL disciplines the oscillator so that itremains more precise. The oscillator can optionally use a differentclock from the clock 550. The oscillator can be configured to generatean RF signal used to transmit data to an external device. A typicalfrequency range for the oscillator is about 10 kHz to about 2600 MHz(e.g., from 10 kHz to 1000 MHz, from 500 kHz to 1500 kHz, from 10 kHz to100 kHz, from 50 kHz to 200 kHz, from 100 kHz to 500 kHz, from 100 kHzto 1000 kHz, from 500 kHz to 2 MHz, from 1 MHz to 2 MHz, from 1 MHz to10 MHz, from 100 MHz to 1000 MHz, from 500 MHz to 2500 MHz, overlappingranges thereof, or any value within the recited ranges). Otherfrequencies can be used, such as can be dependent on the application.The clock 550 is used for timing of the digital controller 548. Atypical frequency of the clock 550 is between about one kilohertz andabout one megahertz (e.g., between 1 kHz and 100 kHz, between 10 kHz and150 kHz, between 100 kHz and 500 kHz, between 400 kHz and 800 kHz,between 500 kHz and 1 MHz, between 750 kHz and 1 MHz, overlapping rangesthereof, or any value within the recited ranges). Other frequencies canbe used depending on the application. A faster clock generally uses morepower than a slower clock.

A return path for a signal sensed from a nerve is optional. Such a pathcan include the amplifier 555, the ADC 557, the oscillator/PLL 560, andthe modulator/power amplifier 562. Each of these items and connectionsthereto can optionally be removed.

In one or more examples, the digital controller 548, the amplifier 555,and/or the stimulation driver circuitry 556, among other components ofthe circuitry 500, can comprise portions of a state machine device. Thestate machine device can be configured to wirelessly receive power anddata signals via the pad(s) 536 and, in response, release or provide anelectrostimulation signal via one or more of the outputs 534. In one ormore examples, such a state machine device needs not retain informationabout available electrostimulation settings or vectors, and instead thestate machine device can carry out or provide electrostimulation eventsafter, and/or in response to, receipt of instructions from the source102.

For example, the state machine device can be configured to receive aninstruction to deliver a neural electrostimulation therapy signal, suchas at a specified time or having some specified signal characteristic(e.g., amplitude, duration, etc.), and the state machine device canrespond by initiating or delivering the therapy signal at the specifiedtime and/or with the specified signal characteristic(s). At a subsequenttime, the device can receive a subsequent instruction to terminate thetherapy, to change a signal characteristic, or to perform some othertask. Thus, the device can optionally be configured to be substantiallypassive, or can be configured to be responsive to received instructions(e.g., contemporaneously received instructions).

A. Circuitry Housing Assemblies

This section describes embodiments and/or features of therapy devices,guiding mechanisms for situating an implantable device (e.g., thetherapy device) within tissue, and/or affixing mechanisms for helpingensure the implantable device does not appreciably move when situatedwithin the tissue. One or more examples regard therapy devices fortreatment of incontinence (e.g., urinary incontinence, fecalincontinence), overactive bladder, pain or other conditions or symptoms,such as those described elsewhere herein.

An advantage of an implantable device discussed in this section (andothers) can include one or more of: (i) a configurable implantabledevice that can be altered in shape and/or electrode configuration tohelp target a site for electrostimulation within a body; (ii) animplantable device that can be implanted and then affixed at a targetlocation (such as an S3 foramen); (iii) an implantable device withimproved signal reception efficiency (e.g., using (1) a dielectricmaterial surrounding an antenna, the dielectric material including adielectric constant that is between a dielectric constant of humantissue and that of air, or (2) multiple antennas in the implantabledevice, such as to include a primary antenna inductively coupled to asecondary antenna), (iv) a thin, discreet implantable device that can beimplanted in narrow areas or thin tissue, such as between skin and bone;(v) an implantable device that can provide an electrostimulation patternthat an elongated tubular implantable device is not able to provide(e.g., due to the location of the electrodes and shape of theimplantable device); and/or (vi) a network of implantable devices thatcan provide a local or wide area stimulation individually or incombination, among others.

In accordance with several embodiments, a system includes an implantabledevice comprising an elongated member having a distal portion and aproximal portion. The device includes a plurality of electrodes, acircuitry housing, circuitry within the circuitry housing adapted toprovide electrical energy to the plurality of electrodes, an antennahousing, and an antenna (e.g., a helical antenna) in the antennahousing. The plurality of electrodes is situated or located along thedistal portion of the elongated member. The circuitry housing isattached to the proximal portion of the elongated member. The circuitryis hermetically sealed or encased within the circuitry housing. Theantenna housing is attached to the circuitry housing at a proximal endof the circuitry housing opposite to an end of the circuitry housingattached to the elongated member.

The system may optionally comprise an external midfield power sourceadapted to provide a power or electrical signal or energy to theimplantable device. The implantable device may be adapted to communicateinformation (e.g., data signals) to an antenna of the external sourcevia the antenna. One, more than one or all the electrodes may optionallybe located at a proximal portion or central portion of the elongatedmember instead of the distal portion. The circuitry housing mayoptionally be attached to a distal portion or central portion of theelongated member. The antenna housing may not be attached to thecircuitry housing or may not be attached to the proximal end of thecircuitry housing. The antenna housing may optionally include adielectric material with a dielectric constant between that of humantissue and air, such as a ceramic material. The ceramic material mayoptionally cover the antenna. The elongated member may optionally beflexible and/or cylindrical. The electrodes may optionally becylindrically-shaped and positioned around a circumference of theelongated member.

The elongated member may optionally include a channel extending throughthe elongated member from a proximal end of the member to the distalportion of the elongated member and a memory metal wire situated in thechannel, the memory metal wire pre-shaped in an orientation to providecurvature to the elongated member. The memory metal may optionally beshaped to conform to a shape of an S3 foramen and generally match acurve of a sacral nerve. The antenna may be a primary antenna and thedevice may further include a secondary antenna in a housing attached tothe antenna housing, the secondary antenna shaped and positioned toprovide a near field coupling with the primary antenna. The device mayoptionally include one or more sutures attached at one or more of: (1) aproximal portion of the antenna housing; (2) a proximal portion of thecircuitry housing; and (3) an attachment structure attached to aproximal end of the antenna housing. The antenna may optionally becoupled to a conductive loop of the circuitry situated in a proximalportion of the circuitry housing. There may be a ceramic materialbetween the antenna and the conductive loop.

There is an ongoing desire to reduce a displacement volume ofimplantable sensor and/or stimulator devices, such as includingneurostimulation devices. Additional miniaturization can allow for aneasier less invasive implant procedure, reduce a surface area of theimplantable device which can in turn reduce a probability ofpost-implant infection, and provide patient comfort in a chronicambulatory patient setting. In some examples, a miniaturized device canbe injected using a catheter or cannula, further reducing invasivenessof an implant procedure.

In an example, a configuration of an implantable neurostimulation deviceis different from a conventional lead implanted with a pulse generator.The implantable stimulation device can include a lead-less design andcan be powered from a remote source (e.g., a midfield source locateddistal to the implantable device).

In an example, a method of making an implantable stimulation device caninclude forming electrical connections at both ends of a circuitryhousing, such as can be a hermetically sealed circuitry housing. Themethod can include forming electrical connections between a feedthroughassembly and pads of a circuit board. In an example, the feedthroughassembly includes a cap-like structure inside of which electrical and/orelectronic components can be provided. A surface of the pads of thecircuit board can be generally perpendicular to a surface of an end offeedthroughs of the feedthrough assembly.

The method can be useful in, for example, forming a hermetic circuitryhousing, such as can be part of an implantable stimulation device orother device that can be exposed to liquid or other environmentalelements that can adversely affect electrical and/or electroniccomponents.

Various traditional assembly techniques can be difficult to apply tominiature devices such as implantable or injectable stimulator devices.For example, wirebonding can be difficult since connections to thesubstrate may be on a surface that is generally perpendicular to afeedthrough. In some examples, wirebonds can be compressed when thecircuitry housing is sealed. Using thin wires that can be compressed tomake connections between the substrate and the board, however, canincrease parasitic capacitance and/or inductance of the RF feedthroughand may detune an RF receiving structure. Further, manufacturing yieldmay be limited through such compression and/or thin wires. Thecompression can break a bond between a wire and a pad or can break thewire itself. The thickness of the wire can affect how likely the wire isto break, for example because a thin wire can be more likely to break,when compressed, than a thicker wire.

FIG. 6 illustrates generally a diagram of an embodiment of a firstimplantable device 600. The device 600 includes a body portion 602,multiple electrodes 604, a circuitry housing 606, and an antenna housing608. The antenna housing 608 encapsulates an antenna 610. Theimplantable device 600 can be configured to sense electrical (or other)activity information from a patient, or to deliver an electrostimulationtherapy to the patient such as using one or more of the electrodes 604.

The body portion 602 can be made of a flexible or rigid material. In oneor more examples, the body portion 602 can include a bio-compatiblematerial. The body portion 602 can include, among other materials,platinum, iridium, titanium, ceramic, zirconia, alumina, glass,polyurethane, silicone, epoxy, and/or a combination thereof.

The body portion 602 includes one or more electrodes 604 thereon or atleast partially therein. The electrodes 604, as illustrated in theexample of FIG. 6, are ring electrodes. In the example of FIG. 6, theelectrodes 604 are substantially evenly distributed along the bodyportion, that is, a substantially equal space is provided betweenadjacent electrodes. Other electrode configurations can additionally oralternatively be used. Some examples of other electrode configurationsare illustrated herein at, e.g., FIGS. 30A-40.

The body portion 602 can include, or can be coupled to, a circuitryhousing 606. In an example, the circuitry housing 606 is coupled to thebody portion 602 at a first end 601 of the body portion 602. In theexample of FIG. 6, the first end 601 of the body portion 602 is oppositea second end 603 of the body portion 602.

The circuitry housing 606 can provide a hermetic seal for electricand/or electronic components 712 (see, e.g., FIG. 7) and/orinterconnects housed therein. The electrodes 604 can be respectivelyelectrically connected to circuitry in the circuitry housing 606 usingone or more feedthroughs and one or more conductors, such as isillustrated and described herein. That is, the circuitry housing 606 canprovide a hermetic enclosure for the electronic components 712 (e.g.,electric and/or electronic components provided inside or encapsulated bythe circuitry housing 606).

In an example, the antenna housing 608 is attached to the circuitryhousing 606 at a first side end 711 (see, e.g., FIG. 7) of the circuitryhousing 606. An antenna 610 can be provided inside the antenna housing608. In an example, the antenna 610 is used for receiving at and/ortransmitting from the device 1200 power and/or data signals. The firstside end 711 is opposite a second side end 713 of the circuitry housing606. In an example, the second side end 713 is an end to which anelectrode assembly, such as including the electrodes 604, or otherassembly, can be electrically connected.

The antenna housing 608 can be coupled to the circuitry housing 606 invarious ways or using various connective means. For example, the antennahousing 608 can be brazed (e.g., using gold or other conductive ornon-conductive material) to the circuitry housing 606. The antennahousing 608 can include an epoxy, tecothane, or other substantiallyradio frequency (RF) transparent (e.g., at a frequency used tocommunicate to/from the device 1200) and protective material.

In one or more examples, the antenna housing 608 can include a ceramicmaterial such as zirconia or alumina. The dielectric constant ofzirconia is similar to a dielectric constant of typical body muscletissue. Using a material with a dielectric constant similar to that ofmuscle tissue can help stabilize the circuit impedance of the antenna610 and can decrease a change in impedance when the antenna 610 issurrounded by different tissue types.

A power transfer efficiency such as from an external transmitter to thedevice 1200 can be influenced by the selection of antenna or housingmaterials. For example, a power transfer efficiency of the device 1200can be increased when the antenna 610 is surrounded or encapsulated by alower permittivity tissue, such as when the antenna housing 608comprises a ceramic material. In an example, the antenna 610 can becomposed as a single ceramic structure with the feedthrough.

FIG. 7 illustrates generally a schematic view of an embodiment of thecircuitry housing 606. The circuitry housing 606 as illustrated includesvarious electric and/or electronic components 712A, 712B, 712C, 712D,712E, 712F, and 712G, such as can be electrically connected to a circuitboard 714. The components 712A-G and the circuit board 714 are situatedwithin an enclosure 722. In an example, the enclosure 722 comprises aportion of the circuitry housing 606.

One or more of the components 712A-G can include one or moretransistors, resistors, capacitors, inductors, diodes, centralprocessing units (CPUs), field programmable gate arrays (FPGAs), Booleanlogic gates, multiplexers, switches, regulators, amplifiers, powersources, charge pumps, oscillators, phase locked loops (PLLs),modulators, demodulators, radios (receive and/or transmit radios),and/or antennas (e.g., a helical shaped antenna, a coil antenna, a loopantenna, or a patch antenna, among others), or the like. The components712A-G in the circuitry housing 606 can be arranged or configured toform, among other things, stimulation therapy generation circuitryconfigured to provide stimulation therapy signals, such as can bedelivered to a body using the electrodes 604, receiver circuitryconfigured to receive power and/or data from a remote device,transmitter circuitry configured to provide data to a remote device,and/or electrode selection circuitry such as configured to select whichof the electrodes 604 is configured as one or more anodes or cathodes.

The enclosure 722 can include a platinum and iridium alloy (e.g., 90/10,80/20, 95/15, or the like), pure platinum, titanium (e.g., commerciallypure, 6Al/4V or another alloy), stainless steel, or a ceramic material(such as zirconia or alumina, for example), or other hermetic,biocompatible material. The circuitry housing 606 and/or the enclosure722 can provide an airtight space for the circuitry therein. A thicknessof a sidewall of the enclosure 722 can be about tens of micrometers,such as can be about ten, twenty, thirty, forty, fifty, sixty, seventy,eighty, ninety, one hundred, one hundred ten, etc. micrometers, or somethickness in between. An outer diameter of the enclosure 722 can be onthe order of less than ten millimeters, such as can be about one, oneand a half, two, two and a half, three, three and a half, etc.millimeters or some outer diameter in between. A length of the enclosurecan be on the order of millimeters, such as can include two, three,four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, etc.millimeters, or some length in between. If a metallic material is usedfor the enclosure 722, the enclosure 722 can be used as part of theelectrode array, effectively increasing the number of selectableelectrodes 604 for stimulation.

Rather than being hermetic, the enclosure 722 can be backfilled toprevent ingress of moisture therein. The backfill material can include anon-conductive, waterproof material, such as epoxy, parylene, tecothane,or other material or combination of materials.

In the example of FIG. 7, the circuitry housing 606 can include a firstend cap 716A and a second end cap 716B. In an example, the caps 716A and716B are situated on or at least partially in the enclosure 722. Thecaps 716A and 716B can be provided to cover openings such as onsubstantially opposite sides of the enclosure 722. The cap 716A forms aportion of the first side end 711 of the circuitry housing 606 and thecap 716B forms a portion of the second side end 713 of the circuitryhousing 606. Each of the caps 716A-B includes one or more conductivefeedthroughs. In the example of FIG. 7, the first end cap 716A includesa first feedthrough 718A, and the second end cap 716B includes secondand third feedthroughs 718B, and 718C. The conductive feedthroughs718A-C provide an electrical path to a conductor connected thereto.

FIG. 8 illustrates generally a cross-section diagram of an embodiment ofthe circuit board 714. FIGS. 9 and 10 illustrate generally top viewdiagrams of respective embodiments of the circuit board 714. The circuitboard 714 as illustrated includes materials stacked to form a layeredcircuit board with one or more portions or materials that are flexible.Referring again to FIG. 8, the illustrated portions or structures of thecircuit board 714 shown enclosed by dashed lines 801 and 803 can includea flexible material. Portions or structures illustrated outside of thedashed lines 801 and 803 can be flexible or rigid.

In the example of FIG. 8, the circuit board 714 includes dielectricmaterial 802 and 812 (e.g., comprising one or more materials having thesame or different dielectric or permittivity characteristics) providedin dielectric material regions 802A, 802B, 812A, and 812B, andconductive material 804 and 806 (e.g., comprising one or more materialshaving the same or different conductivity characteristics) provided inconductive material regions 804A-804F and 806A-806H. The dielectricregions can include the same or different dielectric materials, and theconductive material regions can include the same or different conductivematerials.

In an example, the dielectric material regions 802A and 802B includepolyimide, nylon, polyether ether ketone (PEEK), a combination thereof,or other flexible dielectric material. The dielectric material caninclude a solder mask and/or stiffener such as a polymer, epoxy, orother dielectric solder mask and/or stiffener material. In an example,the dielectric regions 812A and 812B include a stiffener material. In anexample, a solder mask is used to enhance stiffness or rigidity forselect portions of the circuit assembly.

In an example, the conductive material regions 804A, 804B, 804C, 804D,804E, and 804F, comprise a first conductive material, and the conductivematerial regions 806A, 806B, 806C, 806D, 806E, 806F, 806G, and 806H,comprise a second conductive material. In one or more examples, thefirst conductive material can be rolled and/or annealed. The firstconductive material can include copper, silver, nickel, gold, titanium,platinum, aluminum, steel, a combination thereof, or other conductivematerial. The second conductive material can include a solderablematerial (e.g., a material with an ability to form a bond with moltensolder), such as can include one or more of the materials discussed withregard to the first conductive material. In an example, the secondconductive material can include a plating that includes a material thathas a relatively low rate of oxidation, such as can include silver,gold, nickel, and/or tin. In other examples, the conductive materialregions 804A-804F and 806A-806H comprise the same type of material. Thevarious conductive material regions can be used to provide portions ofmating conductors such as can be used to connect the circuit board 714to one or more other devices or components.

In an example, the first dielectric material 802A forms a base layer orbottom layer on which the remaining materials can be stacked ordeposited to form the circuit board 714. Different materials can bestacked or deposited on different areas of the circuit board 714. Forexample, first materials can be stacked on a first surface 809 of thefirst dielectric material 802A and second materials can be stacked on anopposite second surface 811 of the first dielectric material 802A.

In an example, the first conductive material 804A is coupled with thefirst surface 809 of the first dielectric material 802A. The firstconductive material 804A can be coupled with one or more of the firstdielectric material at 802B and/or with the second conductive materialat 806A, 806C, and/or 806D. The first conductive material 804A can beprovided between the first dielectric material (e.g., at 802A and 802B)and the second conductive material (e.g., at 806A, 806C, and 806D). Inan example, the first conductive material 802B extends into and throughone or more flexible portions of the circuit board 714, such as at oneor both of the areas inside of dashed lines 801 and 803.

In an example, a flexibility or rigidity of one or more portions of thecircuit board 714 can be changed by selectively cutting or etching thecircuit board 714. For example, the flexible portions shown enclosed bydashed lines 801 and 803 can be made more flexible by cutting variousfeatures into the board structures (e.g., into the first dielectricmaterial 802A, the first conductive material 804A, etc). For example,laser cutting can be used to remove a partial layer of the materials orsubstrates forming the circuit board 714. In an example, cutting caninclude forming through-holes in the circuit board 714 to removematerials altogether. In an example, a laser cut feature includes one ormore narrow openings or grooves that extend partially across the board,transversely to the length of the circuit board 714 (the lengthdirection is indicated in FIG. 8 by 833). Such cut features can controlrigidity characteristics and curvature of the circuit board 714.

Referring now to the examples of FIG. 8 and FIG. 9 together, the secondconductive material at 806A, 806C, 806D, 806I, 806J, and 806K can becoupled with the first conductive material at 804A. The secondconductive material at 806A, 806C, 806D, 806I, 806J, and 806K can beprovided at or around respective openings or through-holes, such asillustrated at 920A, 920B, 920C, 920D, 920E, and 920F in FIG. 9. Theopenings 920A-F extend from a surface of the second conductive material806A, 806C, 806D, 806I, 806J, and 806K to a respective opposite surfaceof the second conductive material 806H, 806F, and 8056E, respectively(some of which are obscured in the illustrated views). In an example,the openings 920A-F extend through the second conductive material 806A,806C, 806D, 806I, 806J, and 806K, the first conductive material 804A,804C, 804D, and 804F, and the first dielectric material 802A.

In an example, the first dielectric material 802B is coupled with thefirst conductive material 804A and the first conductive material 804B.The first dielectric material 802B can be provided on the firstconductive material 804A. The first dielectric material 802B can beprovided between the first conductive material at 804A and the firstconductive material at 804B. The first dielectric material 802B can beprovided between the second conductive material at 806A and the secondconductive material at 806C, and with an unoccupied portion of the layercorresponding to the flexible portions of the circuit board 714 (e.g.,corresponding to the areas in FIG. 8 enclosed by dashed lines 801 and803).

The first conductive material 804B can be coupled with the firstdielectric material 802B and the second conductive material 806B. Thefirst conductive material 804B can be provided on the first dielectricmaterial 802B. The first conductive material 804B can be providedbetween the first dielectric material 802B and the second conductivematerial 806B. The first conductive material 804B can be providedbetween the second conductive material 806A and the second conductivematerial 806C, such as with an open space corresponding to the flexibleportions of the circuit board 714 (e.g., corresponding to the areas inFIG. 8 enclosed by dashed lines 801 and 803). Various couplings and/orinterfaces between or among the dielectric material regions 802A, 802B,812A, and 812B, and conductive material regions 804A-804F and 806A-806Hcan be provided as illustrated in FIG. 8 or otherwise.

The flexible portions of the circuit board 714 can have differentdimensions. For example, a first flexible portion of the circuit board714 indicated by the dashed line 801 can have a first length 805, and asecond flexible portion of the circuit board 714 indicated by the dashedline 803 can have a different second length 807. In the example of FIG.8, the second length 807 is less than the first length 805.

In an example, the second conductive material 806A, 806H, and 806K canbe connected to the antenna 610. The length of the flexible portion neara first end 817 of the circuit board 714 affects a parasitic inductanceand/or capacitance that affects the antenna 610. Thus, the second length807 can be selected to reduce such parasitic capacitances and/orinductances. In an example, the first length 805 can be greater than adistance 723 (see FIG. 7). The distance 723 is illustrated as extendingfrom an end 625 (see FIG. 7) of the dielectric material 802B to an endof the enclosure 722. The first length 805 can be selected such that theopenings 920C-F (see FIG. 9) are outside the enclosure 722 when theopenings 920A-B correspond to respective feedthroughs 718A (otherfeedthrough obscured in the view of FIG. 7) and the cap 716A is situatedon, or at least partially in, the enclosure 722.

The circuit board 714 can have a board length that extends from itsfirst end 817 to an opposite second end 819. In an example, a length(indicated by 833) of the circuit board 714 from its first end 817 to adistal end of the flexible portion indicated by the dashed lines 801 canbe greater than a length of the enclosure 722 (e.g., indicated by 727 inFIG. 7). This length or distance relationship can allow the portion ofthe circuit board 714 on which the openings 920C-F (see FIG. 9) or pads1102 (see FIG. 10) reside to turn or flex away from the central portionof the circuit board 714 such that the openings 920C-F or pads 1102 canbe coupled to the cap 716A. A portion of the circuit board 714 betweenthe first flexible portion and the second flexible portion, such asindicated by the dashed lines 835, can be flexible or rigid. Asexplained herein, rigidity characteristics of one or more portions ofthe circuit board 714 can be provided by solder, solder mask, electricand/or electronic components, one or more of the conductive materials804 and 806 and/or one or more of the dielectric materials 802A, 802Band 812A, 812B, among other materials or techniques.

In an example, an embodiment of circuit board can have two rigidportions coupled by a flexible portion. For example, an elongatedcircuit board assembly can include, in order along its lengthwisedirection, a proximal portion (e.g., corresponding to one or more of802A, 804A, 804F, 806A, and/or 806H, near the proximal first end 817 ofthe board in the example of FIG. 8), a flexible portion (e.g.,corresponding to one of the regions 801 and 803 in the example of FIG.8), and a distal portion (e.g., corresponding to one or more of 804C,804D, 806C, 806C, 806E, and/or 806F, near the distal second end 819 ofthe board in the example of FIG. 8). A hermetic enclosure can beconfigured to enclose the elongated circuit board assembly. In anexample, the proximal and distal portions can be asymmetrical and canhave different length characteristics.

FIGS. 9 and 10 illustrate respective embodiments of circuit boards 714Aand 714B, such as can be embodiments of the circuit board 714. Thecircuit board 714A is similar to the circuit board 714B, however thecircuit board 714B includes pads 1102, such as can optionally includesolder bumps, instead of vias or througholes, such as can be formedusing e.g., the second conductive material 806A-K and the openings920A-F. In an example, the circuit board 714A can be coupled or solderedto pins of the feedthroughs 718A-C. In an example, the circuit board714B can be coupled to other components using a solder reflow technique,for example to couple the circuit board 714B to one or more pins (see,e.g., pins 1110 in the examples of FIGS. 16-18). While the example ofthe circuit board 714A includes vias and no pads, and the example of thecircuit board 714B includes pads and no vias, other examples can includea combination of pads and/or vias and the caps 716A-B can be configuredto accommodate such pads and/or vias. For example, the first end cap716A can include one or more feedthroughs 718A while the second end cap716B can include pads, or one cap can include feedthroughs 718A and pads1102.

FIGS. 11-15 and 7 illustrate operations of an embodiment of a methodthat includes electrically connecting and enclosing the circuit board714 in the circuitry housing 606. FIG. 11 illustrates an embodiment of adevice 1100 that includes the electrical and/or electronic components712A-G coupled to the circuit board 714. The circuit board 714 andcomponents 712A-G are discussed generally above.

FIG. 12 illustrates an embodiment of a device 1200 that includes thedevice 1100 and the first end cap 716A. In an example, the device 1200includes the second conductive material 806A, 806K, and/or 806Helectrically connected to respective feedthroughs of the first end cap716A, such as can include the feedthrough 718A.

FIG. 13 illustrates an embodiment of a device 1300 that includes thedevice 1200 and the enclosure 722. In the example of FIG. 13, thecircuit board 714 and its components are provided inside of theenclosure 722. The first end cap 716A can be aligned with a firstopening in the enclosure 722, and the cap can include one or moreportions that extend at least partially inside of the enclosure 722. Inthe example of FIG. 13, a flexible distal portion of the circuit board714 extends beyond an end 1331 of the enclosure 722, the end 1331 beingopposite to the first opening in the enclosure 722. Electrical couplingsprovided on the extension portion of the circuit board 714, such asincluding the flexible distal portion, can be used to electricallycouple the circuit board 714 (or one or more components thereon) withthe second end cap 716B. That is, having the extension portion of thecircuit board 714 can help facilitate making electrical connectionsbecause the connection task can be performed at least partially outsideof the housing or enclosure 722.

FIG. 14 illustrates an embodiment of a device 1400 that includes thedevice 1300 and the second end cap 716B. In the example of FIG. 14, thecircuit board 714, or one or more of the components coupled to thecircuit 714, is electrically coupled to one or more of the feedthroughs718B and 718C, and the feedthroughs 718B and 718C are coupled to thesecond end cap 716B. In an example, the second conductive material at806C-D and/or 806I-J can be soldered or otherwise electrically coupledto respective locations on the feedthroughs 718B and 718C.

FIG. 15 illustrates an embodiment of a device 1500 that includes thedevice 1400 and the second end cap 716B installed is situated on the end1331 of the enclosure 722. The first and second end caps 716A and 716Bare provided or installed on opposite ends of the enclosure 722. Thesecond end cap 716B can include one or more portions that extend atleast partially inside of the enclosure 722.

Referring again to FIG. 7, the device 1500 is illustrated with the firstand second end caps 716A and 716B coupled to the enclosure 722. The capscan be coupled to the enclosure 722 using various attachment processes,such as including brazing, welding, or other process. The example ofFIG. 7 illustrates weld/braze marks 720A-720D that indicate that thefirst and second end caps 716A and 716B are affixed to the enclosure722. Variations on the example method illustrated in FIGS. 7 and 11-15can similarly be performed. For example, the first end cap 716A can bewelded, brazed, bonded, or otherwise attached to the enclosure 722before the circuit board 714 is coupled to the second end cap 716B.

FIG. 16 illustrates generally an example of a top view of an end cap1600. In an example, the end cap 1600 corresponds to embodiments of thefirst and/or second end cap 716A and 716B. The example end cap 1600includes a first dielectric material 1606, a connective material 1608, aflange material 1601, and a plurality of pins 1110. The dielectricmaterial 1606 can include alumina, zirconia, sapphire, ruby, acombination thereof, or the like. The dielectric material 1606 can besubstantive non-electrically conductive and securable to the flangematerial 1601. The flange material 1601 can include a metallic material,such as can include a platinum iridium alloy (e.g., 90/10, 95/15, 80/20,or the like), pure platinum, 6AL/4V titanium, 3Al/2.5V titanium, puretitanium, niobium, a combination thereof, or the like. In an example,the flange material 1601 can surround the dielectric material 1606. Inthe example of FIG. 16 that includes a circular profile, the dielectricmaterial 1606 is concentric with the flange material 1601. In anexample, the pins 1610 are hollow and conductive, and can comprise thesame or similar materials as discussed above for the first and secondconductive materials, such as at 804A-F and/or 806A-K.

The top view of FIG. 16 shows a first surface 1103 of the dielectricmaterial 1606. The pins 1610 can extend from the first surface 1603 toan opposite second surface 1605 of the dielectric material 1606. In anexample, each of the pins 1610 can be brazed welded, or otherwisehermetically sealed within the dielectric material 1606.

FIG. 17 illustrates generally an example of a cross-section view of theend cap 1600. The cross-section view shows the first and opposite secondsurfaces 1603 and 1605 of the end cap 1600. The cross-section view alsoshows the multiple pins 1610 that extend from the first surface 1603 tothe second surface 1605, such as through the dielectric material 1606.In the example of FIG. 17, end portions of each of the pins 1610includes a conductive adhesive 1612 provided at the second surface 1605.The conductive adhesive 1112 can include a solder, conductive paste, orother conductive material that can be used to electrically couple thepins 1610 of the end cap 1600 to another component. In an example, theconductive adhesive 1612 comprises solder bumps.

Referring now to FIGS. 6 and 17, the body portion 602 can be coupled tothe circuitry housing 606 using the end cap 1600. In an example, thecoupling can use conductive material coupled to the pins 1610 and canadditionally or alternatively include welding or brazing the bodyportion 602 to the end cap 1600. In an example, the pins 1610 comprisehollow portions or receptacles that are configured to receive conductivemembers from the body portion 602.

FIG. 18 illustrates generally an example of a cross-section view of anassembly 1800 that includes the end cap 1600 and a circuit board 714C.The circuit board 714C can have the same or similar construction to oneof the circuit boards 714, 174A, and/or 714B discussed herein. In anexample, the circuit board 714C is similar to the circuit board 714Bshown in FIG. 10, however with the circuit board 714C includingadditional pads 1102 than are illustrated in the example of the circuitboard 714B. In the example of FIG. 18, the assembly 1800 includes theend cap 1600 electrically coupled to the circuit board 714C. Forexample, the conductive adhesive 1612 can be reflowed to adhere to thepads 1102.

In an example, an epoxy or other underfill material 1604 can be providedbetween the dielectric material 1606 and the circuit board 714C, such asto provide additional mechanical support and connectivity between thecircuit board 714C and the dielectric material 1606, such as additionalto any such connectivity provided by the electrical connections formedbetween the pads 1102 and the conductive adhesive 1612, and/or asinsulation from shorts between the electrical connections.

A circuitry housing for an implantable device, such as the circuitryhousing 606 as previously discussed, can include electric or electroniccomponents for providing stimulation to a patient in which theimplantable device is implanted. Also, as previously discussed, thecircuitry housing can include one or more plates and/or feedthroughs(e.g., comprising a portion of one or more end caps), such as to sealthe circuitry housing and/or provide electrical signals from within thecircuitry housing to outside of the circuitry housing. The plates and/orfeedthroughs can be made small, such as to help reduce or minimize avolume of the implantable device assembly. The present inventors haverecognized, among other things, that a problem to be solved includesminiaturizing the plates and/or feedthroughs. The present inventors haverecognized that a problem includes forming a feedthrough or plate thatis less than about 3 millimeters in diameter. A solution to the problemcan include selecting appropriate materials and assembly processes, asdescribed herein.

By reducing a diameter of the end caps of the circuitry housing, theimplantable device can require a smaller opening in the patient than isrequired for larger, previous implantable devices. A sheath (a lumenthrough which the implantable device is inserted into a patient) can bemade with a smaller diameter as well. The implantable device may besufficiently small to allow an implant procedure that does not use asheath. In one or more examples, a body portion of an implantable devicethat includes electrodes (e.g., ring electrodes) situated thereon can bereplaced or augmented with one or more electrodes on the cap. Such aconfiguration can further reduce an overall length of the implantabledevice, reduce a displacement volume of the implantable device, reduce arisk of infection, and/or reduce costs associated with making and/orinstalling the implantable device.

FIG. 19 illustrates generally an example of a top view of a dual-portcap 1900. FIG. 20 illustrates generally a cross-section view of thedual-port cap 1900. The dual-port cap 1900 is similar to the end cap1600, with the cap 1900 including feedthroughs 718D and 718E instead ofpins 1610. The cap 1900 is considered a “dual-port” cap because itincludes a pair of feedthroughs or electrical ports. The feedthroughs718D and 718E can extend or protrude away from the opposite sidesurfaces of the dual-port cap 1900, such as illustrated in FIG. 20. Thatis, portions of the feedthroughs 718D and 718E can include extensionportions that extend way from the first and/or opposite second sides1903 and 1905 of the cap.

In the example, the dual-port cap 1900 includes the flange material1601, the dielectric material 1606, welded or brazed connective material1608, and another connective material 1906 such as can be welded orbrazed material around the feedthroughs 718D and 718E. The connectivematerial 1906 can include gold, ruthenium, platinum, rhodium, palladium,silver, osmium, iridium, platinum, a combination thereof, or other noblematerial, or like material. The connective material 1906 can form a bondand/or seal a gap between the feedthroughs 718D and 718E and thedielectric material 1606. The feedthroughs 718D and 718E can include aconductive material, such as discussed previously regarding thefeedthroughs 718A-C, and/or can include platinum, iridium, or acombination thereof, such as can include about eighty to a about onehundred percent platinum and the remainder being iridium. The dielectricmaterial 1606, as previously discussed, can include a ceramic, such ascan include alumina and/or zirconia. The flange material 1601, in one ormore examples, can include a same or similar material as that of thefeedthroughs 718D and 718E.

A diameter 1902 of the feedthroughs 718D and 718E can be less than onemillimeter to e.g., several millimeters, such as can include abouttenths of a millimeter, half a millimeter, one millimeter, one and ahalf millimeters, two millimeters, etc. or some diameter in between. Adiameter 1904 of the dual-port cap 1900 can be between about 5 and about9 French (e.g., about 1.67 millimeter and about 3 millimeters), such ascan be about 7 French or less than about 3 millimeters and greater thanabout 1.5 millimeters.

FIG. 20 illustrates generally an example that includes a cross-sectionview of the dual-port cap 1900. In the example, the flange material 1601can extend or protrude past a second surface 1605 of the dielectricmaterial 1606. The flange material 1601 can be generally flush with thedielectric material 1606 at a first surface 1603. The feedthroughs 718Dand 718E extend or protrude past the second surface 1605 and the firstsurface 1603. Welded or brazed connective materials 1608 and 1906 can beused to mechanically connect the flange material 1601 to the dielectricmaterial 1606, and to mechanically connect the feedthroughs 718D and718E to the dielectric material 1606, respectively. In an example, thewelded or brazed materials discussed herein, such as the welded orbrazed materials connective 1608 or 1906, can provide a hermetic seal,such that substantially no foreign matter can travel through the cap1900 and into the enclosure 722. The feedthroughs 718D and 718E can beelectrically connected to an antenna at or near one end thereof and tothe circuit board 714 at or near the other, opposite end.

FIG. 21 illustrates generally an example of a top view of amultiple-port cap 2100. The cap 2100 can be used in place of one or moreof the other caps discussed herein. In the example of FIG. 21, themultiple-port cap 2100 has a rectangular profile. The cap 2100 includescomponents similar to other caps discussed herein, with the shapes ofsome of the components being different than those previously illustratedor discussed herein. In an example, the cap 2100 includes electrode caps2102 and a push rod assembly 2104.

The electrode caps 2102 can include one or more conductive materials,such as can be similarly used in the feedthroughs 718A-G, the connectivematerial 1608 and/or 1906, the pins 1610, or other conductive material.The push rod assembly 2104 can provide a location at which to attach apush rod that can be used to situate the cap 2100 (and the circuitryattached thereto, see FIG. 23) within a patient, such as during animplant procedure. The push rod assembly 2104 can include an attachmentmechanism (not shown), such as a threaded hole, a detent, or the like,to which the push rod can be attached.

FIG. 22 illustrates generally an example that includes a cross-sectionview of the multiple-port cap 2100. The flange material 1601 of the cap2100 is illustrated as including a stepped profile. The dielectricmaterial 1606 can include a matching (e.g., mirroring) stepped profile,such that a step of the dielectric material 1606 mates with a step ofthe flange material 1601. Similarly to the other embodimentsillustrated, the connective material 1608 and 1906 can mechanicallyconnect the flange material 1601 to the dielectric material 1606, andcan mechanically connect the feedthroughs to the dielectric material1606, respectively.

In an example, the electrode caps 2102 can be pressed on or cast as partof the feedthroughs 718F and/or 718G. A distance from a tip of each ofthe electrode caps 2102 to the first surface 1603 can be different orthe same for different feedthroughs. The cap 2100 as illustratedincludes six feedthroughs and corresponding electrode caps 2102. The cap2100 can include fewer or more feedthroughs and electrode caps, such ascan include one, two, three, four, five, or more electrode caps andcorresponding feedthroughs.

In an example, the cap 2100 can include an optional dielectric coating2106, such as illustrated in FIG. 22. The dielectric coating 2106 canhelp prevent shunting of magnetic and/or electric fields providedthrough the electrode caps 2102. The dielectric coating 2106 can includeParylene, other conformal coating, or other dielectric material that canbe situated on the surface 1603.

FIG. 23 illustrates generally an example of a side view of an embodimentof a device 2300 that includes the multiple-port cap 2100. The device2300 includes an enclosure 722A with the cap 2100 situated on andattached to the enclosure 722A, such as to seal the enclosure 722A frommoisture or other material intrusion. The circuit board 714 (andassociated electric and/or electronic components attached thereto) andthe antenna 610 are illustrated as being inside of the enclosure 722A(indicated by the dashed lines). Feedthroughs 718F, 718H, and 718I areelectrically connected to the circuit board 714, such as through wirebonds 2108.

FIG. 24 illustrates generally an example of a side view of an embodimentof an implantable device 2400. The implantable device 2400 can include adielectric end cap 2406, electrodes 604, a dielectric section 2404, anelectrode end cap 2402, welded or brazed material connective material1608, the circuit board 714, the antenna 610, and electricalconnection(s) 2108. The dielectric end cap 2406 can be made of alumina,zirconia, other ceramic material, or the like. The dielectric section2404 can be made of the same or a different material as the dielectricend cap 2406.

In an example, the electrode end cap 2402 can be made of a conductivematerial, such as can include a same or similar material as thefeedthroughs discussed herein. The dielectric section 2404 can be weldedor brazed to the electrodes 604 such as at opposite sides of thedielectric section 2404. Welded or brazed connective material 1608 canbe provided at or around a perimeter of the electrodes 604, such as tohermetically seal the circuit board 714 from matter external to thedevice 2400. In one or more examples, the antenna 610 is provided insidethe end cap 2406 and a cap, such as the cap 716 or 2100, can be used toelectrically connect the antenna 610 to the circuit board 714. One ormore of the embodiments discussed herein can include a hermeticallysealed enclosure, such as to include a measured Helium leak rate lessthan 10⁻⁹ cubic centimeters (cc)-atmosphere (atm)/second (sec) afterassembly.

B. Elongated Implantable Assemblies

As similarly discussed elsewhere herein, using an external wirelesspower transmitter to power an implantable device can be difficult,especially when the implantable device is deeply implanted. Embodimentsdiscussed herein can help overcome such a difficulty, for example usingan implantable device with an extended length characteristic. In someembodiments, a distance between a wireless power transmitter (e.g.,external to the patient body) and an antenna of an implanted device isless than an implantation depth of electrodes on the implantable device.Some embodiments can include an elongated portion, such as betweencircuitry housings, that can extend a length of an implantable device.

The present inventors have recognized a need to increase an operatingdepth for devices that provide neuro stimulation pulses to tissue.Embodiments can allow an implantable device (e.g., an implantable neurostimulation device) to: (a) deliver therapy pulses to deep nerves (e.g.,nerves at the center of a torso or deep within a head, e.g., at a depthgreater than ten centimeters); and/or (b) deliver therapy pulses deepwithin vascular structures requiring stimulation originating fromlocations deeper than currently available using other wirelesstechnologies. In an example, some structures internal to the body may bewithin about 10 cm of a surface of the skin, but may nonetheless not bereachable using earlier techniques. This can be because an implant pathmay not be linear or electrodes of the device may not be able to reachthe structure due to bends or other obstacles in the implant path.

The present inventors have recognized that a solution to thisimplantation depth problem, among other problems, can include animplantable device that is configured to function at various depths byseparating proximal circuitry (e.g., circuitry situated in a proximalcircuitry housing and generally including communication and/or powertransceiver circuitry) into at least two portions, and providing anelongated (e.g., flexible, rigid, or semi-rigid) portion between the twocircuitry portions. A more proximal portion of the circuitry (e.g.,relative to the other circuitry portion) can include power receptionand/or signal conditioning circuitry. A more distal portion of thecircuitry (e.g., more distal relative to another circuitry portion) caninclude stimulation wave production circuitry. The more proximal housingis designated in the following discussion as the first circuitryhousing, and the more distal housing is designated as the secondcircuitry housing.

Electrically sensitive radio frequency (RF) receiving and/or backscattertransmitting circuitry components can be provided or packaged in theproximal first circuitry housing. In an example, a received RF powersignal may be rectified to direct current (DC) in the first circuitryhousing, such as for use by circuitry disposed in the same or otherportions of the assembly. Backscatter transmitting circuitry canoptionally be provided. In an example, the first circuitry housing canbe maintained within a sufficiently minimal distance to be powered by anexternal power transmitter, such as a midfield powering device, nearfield communication, or the like, such as including a midfield poweringdevice described hereinabove.

FIG. 25 illustrates generally an example of an elongated implantabledevice 2500. The implantable device 2500 can include an elongatedportion 2502, a first circuitry housing 606A, a second circuitry housing606B, and a connector 2504. In the example of FIG. 25, the connector2504 is frustoconical, however, other shapes or configurations cansimilarly be used. The second circuitry housing 606B is optional and theelongated portion 2502 can connect directly to the frustoconicalconnector 2504. In an example, the first circuitry housing 606A includescommunication circuitry, such as for receiving wireless power signalsand/or communicating data to or from an external device. Variouscircuitry in the second circuitry housing 606B can include anapplication specific integrated circuit (ASIC), large-footprintcapacitors, resistors, and/or other components configured to generatetherapy signals or pulses, and can electrically connect to theelectrodes 604.

The elongated portion 2502 separates the first and second circuitryhousings 606A and 606B. The elongated portion 2502 can optionallyinclude conductive material 2512A and 2512B (e.g., one or moreconductors) extending therethrough or thereon. In an example, theconductive material 2512A and 2512B can electrically connect aconductive feedthrough of the first circuitry housing 606A to aconductive feedthrough of the circuitry housing 606B. In an example, theconductive material 2512A and 2512B is configured to carry the OUTPUT+and/or OUTPUT− signals, respectively (see, e.g., FIGS. 27 and 28).

The conductive material 2512A and 2512B can include copper, gold,platinum, iridium, nickel, aluminum, silver, a combination or alloythereof, or the like. The elongated portion 2502 and/or a coating on theconductive material 2512A and 2512B can electrically insulate theconductive material 2512A and 2512B from a surrounding environment, suchas can include body tissue when the device is implanted in a patientbody. The coating can include a dielectric, such as an epoxy and/orother dielectric material. The elongated portion 2502 can include adielectric material, such as a biocompatible material. The dielectricmaterial can include Tecothane, Med 4719, or the like.

In an example, the elongated portion 2502 can be formed from or coatedwith a material that enhances or increases friction with respect to anexpected material within which the device is configured to be implanted(e.g., body tissue). In an example, the materials include silicone.Additionally, or alternatively, a rough surface finish can be applied toa surface, or a portion of the surface, of the elongated portion 2502. Afriction-increasing material and/or surface finish can increase frictionof the implant relative to the biological tissue in which theimplantable device can be implanted. Increasing friction can help theimplantable device maintain its position within the tissue. In one ormore examples, other small-scale features, such as protrusions (e.g.,bumps, fins, barbs, or the like) can be added to increase friction inone direction. Increasing friction can help improve chronic fixation sothat the implantable device is less likely to move (e.g., in an axial orother direction) while implanted.

A dimension 2506A (e.g., a width, cross-sectional area, or diameter) ofthe first circuitry housing 606A can be about the same as acorresponding dimension 2506B (e.g., a width) of the circuitry housing606B. The elongated portion 2502 can include a first dimension 2508(e.g., a width) that is about the same as the dimensions 2506A and 2506Bof the first and second circuitry housings 606A and 606B, respectively.A second dimension 2510 (e.g., width) of a distal portion of theimplantable device 2500 can be less than the dimensions 2506A and 2506Band 2508.

In an example, the distal portion of the implantable device 2500includes the body portion 602, one or more electrodes 604, and othercomponents coupled to a distal side of a frustoconical connector 2504. Aproximal portion of the implantable device 2500 includes the first andsecond circuitry housings 606A and 606B, the elongated portion 2502, theantenna 610, and other components on a proximal side of thefrustoconical connector 2504. The dimensions 2506A and 2506B, 2508, and2510 as illustrated are generally perpendicular to a length dimension2514 of the components of the device 2500.

The frustoconical connector 2504 includes a proximal side 2516 coupledto the proximal portion of the implantable device 2500. Thefrustoconical connector 2504 includes a distal side 2518 coupled to thedistal portion of the implantable device 2500. The distal side 2518 isopposite the proximal side 2516. A width or diameter dimension of thedistal side 2518 can be about the same as the corresponding dimension2510 for the body portion 602. A width or diameter dimension of theproximal side 2516 can be about the same as the corresponding dimension2506A and/or 2506B.

In one or more examples, a length 2514 of the device 2500 can be betweenabout fifty millimeters to about hundreds of millimeters. In one or moreexamples, the elongated portion 2502 can be between about tenmillimeters to about hundreds of millimeters. For example, the elongatedportion 2502 can be between about ten millimeters and about one hundredmillimeters. In one or more examples, the dimension 2510 can be aboutone millimeter (mm) to about one and one third mm. In one or moreexamples, the dimensions 2506A and 2506B can be between about one and ahalf millimeters and about two and a half millimeters. In one or moreexamples, the dimensions 2506A and 2506B can be between about one andtwo-thirds millimeters and about two and one-third millimeters. In oneor more examples, the dimension 2508 can be between about one millimeterand about two and a half millimeters. In one or more examples, thedimension 2508 can be between about one millimeter and about two andone-third millimeters.

FIG. 26 illustrates generally an example of a system 2600 that includesthe implantable device 2500 implanted within tissue 2604. The system2600 as illustrated includes the implantable device 2500, tissue 2604,an external power unit 2602, and a wire 2606 (e.g., a push rod, suture,or other component to implant or remove the implantable device 2500). Inan example, the external power unit 2602 includes the external source102.

The elongated portion 2502 of the device 2500 allows the electrodes 604of the implantable device 2500 to reach deep within the tissue 2604 andallows the antenna to be sufficiently close to the tissue surface andthe external power unit 2602. The device 2500 is illustrated with theelongated portion bent, such as to illustrate that the elongated portioncan stretch (e.g., a portion is stretchable and/or can be elongated)and/or flex (e.g., can be rotated about one or more axes along thedevice's length).

In one or more examples, the external power unit 2602 can include amidfield power device, such as the external source 102 described herein.While the circuitry illustrated in FIGS. 27 and 28 is generallyconfigured for midfield powering embodiments, the two-part proximalassembly package (e.g., a device that includes the first and secondcircuitry housings 606A and 606B with the elongated portion 2502therebetween) can be applied to other wireless embodiments, includinginductive nearfield, far-field, capacitively coupled, and/orultrasonically powered implantable devices.

FIG. 27 illustrates generally a schematic example of first circuitrysuch as can be provided in the first circuitry housing 606A. The firstcircuitry housing 606A can be electrically connected to differentialradio frequency (RF) lines 2704A and 2704B. The differential RF lines2704A and 2704B can be electrically connected to respective connectionsfrom the antenna 610. In an example, the differential RF lines 2704A and2704B can be electrically connected to respective feedthrough conductors718 of the first circuitry housing 606A.

Circuitry 2702 within the first circuitry housing 606A can operate onthe differential RF lines 2704A and 2704B to produce a differential RFoutput on the plus 2706A and minus 2706B lines. The output waveform maybe a sinusoidal or square waveform. The output plus 2706A and outputminus 2706B lines can be electrically coupled to electrical conductorson another feedthrough of the first circuitry housing 606A. The RF plusline 2704A and RF minus line 2704B can be coupled to feedthroughs thatare provided on a first side of the first circuitry housing 606A, suchas opposite to feedthroughs on an opposite side of the first circuitryhousing 606A to which the output plus 2706A and output minus 2706B linesare connected. The output plus 2706A and output minus 2706B lines canprovide a signal that is between about one and ten volts, peak-to-peak,for example. The signals provided on the output plus 2706A and outputminus 2706B lines can be charge balanced, such as by one or morecomponents of the circuitry 2702.

At least a portion of circuitry of the implantable device 2500 can behoused within the first circuitry housing 606A. The portion asillustrated is circuitry 2702. The circuitry 2702 can include, amongother things, a pulse width modulator 2708, a clock generator 2710, acontroller 2712, a differential rectifier 2714, backscatter switchingload circuitry 2716, a load detector 2718, and an encoder/decodercircuit 2720. The circuitry 2702 can include other electrical and/orelectronic components, such as resistors, transistors, inductors,capacitors, diodes, multiplexers, amplifiers, or the like. These othercomponents can help condition the electrical signals, such as to helpensure that the signals include sufficient voltage, current, or power,such as to help ensure that the current, voltage, or power remain withinspecified operating ranges of the circuitry 2702.

The pulse width modulator 2708 (sometimes referred to as a pulseduration modulator) encodes a message into a pulse signal. The pulsewidth modulator 2708 controls power supplied to other components of thecircuitry 2702 or 2802. An average value of power (voltage and current)fed to a load can be controlled by altering an amount of time the pulseis high, low, and/or at a ground or reference level potential, that is,by adjusting a duty cycle of the signal.

The clock generator 2710 is a circuit that produces a clock signal. Inan example, the controller 2712 and other clocked components can use theclock signal to time its operations. The clock signal produced by theclock generator 2710 can include a square wave, or other wave with arising edge and/or a falling edge. Basic circuitry included in a clockgenerator generally includes a resonator and an amplifier. The clocksignal generated by the clock generator 2710 can be within a Megahertzrange, but other ranges can similarly be used or provided by thecircuit.

The controller 2712 provides control signals that configure othercircuitry to perform operations in accord with the control signals. Forexample, the controller 2712 can configure a duty cycle provided by thepulse width modulator 2708, or can configure whether the backscatterswitching load provides a signal to the antenna 610 for transmitting tothe external power unit 2602, or the like.

The differential rectifier 2714 receives an alternating current (AC)signal and produces a DC signal. A capacitor can be coupled to an outputof the differential rectifier 2714, such as to help smooth the output.The connections between and/or circuitry of the first and secondcircuitry housings 606A and 606B can help transfer energy from one ofthe housings to the other such as without exposing any non-hermeticallyencased signal processing circuitry to a non-charge balanced signal.

The backscatter switching load circuitry 2716 can switch between areceive mode and a transmit mode. The backscatter switching loadcircuitry 2716 can receive power from the external power unit 2602 (inreceive mode). The backscatter switching load circuitry 2716 cantransmit reflected power from the external power unit 2602 back to theantenna 610, such as to transmit the reflected power to the externalpower unit 2602. The reflected power can encode data communications fromthe implantable device 2500 to the external power unit 2602. In anexample, the encoded data includes information about a power transferefficiency between the device 2500 and the external power unit 2602.

The load detector 2718 detects whether and/or how much power is drawn bycircuitry 2702, circuitry 2802 (see FIG. 28), or other components of thedevice 2500. The controller 2712 can use an output of the load detector2718 to adjust a PWM duty cycle or other parameter of the circuitry2702.

The encoder/decoder circuit 2720 can be configured to convert data fromone format to another format. The encoder/decoder circuit 2720 receivesa rectified wave and determines whether configuration data or other datais embedded in the rectified wave. The encoder/decoder circuit 2720 canreceive a backscatter signal, such as from the backscatter switchingload circuitry 2716 and encode the signal with data to be transmitted tothe external power unit 2602.

FIG. 28 illustrates generally a schematic example of second circuitrysuch as can be provided in the circuitry housing 606B. Althoughparticular examples or types of circuitry are discussed as being in aparticular one of the first and second circuitry housings 606A and 606B,the various circuits can optionally be provided in either locationdepending on various design constraints and optimizations.

In the example of FIG. 28, the second circuitry housing 606B iselectrically connected to the output plus 2706A and the output minus2706B lines from the first circuitry housing 606A (see, e.g., FIG. 27).The output plus 2706A and output minus 2706B lines can be electricallyconnected to respective connections from within the first circuitryhousing 606A. In an example, the output plus 2706A and output minus2706B lines can be electrically connected to respective feedthroughconductors 718 of proximal sides the second circuitry housing 606B.

A portion of circuitry of the implantable device 2500 can be housedwithin the second circuitry housing 606B. The portion as illustrated inFIG. 28 includes various circuitry 2802. The circuitry 2802 includes afull wave rectifier 2808, a voltage multiplier 2810, a DC-DC converter2812, a stimulation driver 2814, a multiplexer 2816, a load modulator2818, and a decoder 2820. The circuitry 2802 can include otherelectrical and/or electronic components, such as resistors, transistors,inductors, capacitors, diodes, multiplexers, amplifiers, or the like.These other components can help condition various electrical signals,such as to help ensure that the signals include sufficient voltage,current, or power, such as to ensure that the current, voltage, or powerremain within specified operating ranges of the circuitry 2802. Thesecond circuitry housing 606B can further include or provide a housingfor capacitors 2822A, 2822B, 2822C, 2822D, 2822E, 2822F, 2822G, and2822H. In an example, the capacitors 2822A-2822H can help removeundesired high frequency components from stimulation signals, such ascan be present on electrode conductor lines 2804A, 2804B, 2804C, 2804D,2804E, 2804F, 2804G, and/or 2804H, respectively. In an example, thecapacitors 2822A-2822H can block direct current voltages on respectiveelectrode lines 2804A-2804H, respectively.

A full wave rectifier can convert a wave signal, such as a sine wavesignal, to a signal that includes one of positive or negative components(and ground). In an example, the full wave rectifier 2808 converts awave that is positive, negative, or both, to a wave that includes onlyone of positive or negative components.

The voltage multiplier 2810 includes electrical circuitry that convertsan AC power signal from a low voltage to a higher DC voltage. The DC-DCconverter 2812 includes circuitry that converts a DC voltage signal to adifferent voltage.

The stimulation driver 2814 includes circuitry that configures othercircuitry 2802 to provide stimulus to the tissue 2604. The stimulationdriver 2814 can provide signals to the multiplexer 2816, and themultiplexer 2816 can in turn select which of lines 2804A, 2804B, 2804C,2804D, 2804E, 2804F, 2804G, and 2804H to use to provide stimulationand/or to use for electrical signal sensing. In an example, a controlsignal input to the multiplexer 2816 indicates which electrode(s) 604provide a cathode and which electrode(s) 604 provide an anode forsignals provided by the stimulation driver 2814.

The load modulator 2818 can vary a frequency of a signal provided as astimulus. In an example, the load modulator 2818 can adjust a duty cycleof the signal provided as stimulus.

The decoder 2820 can be configured to convert data signals. In anexample, the decoder 2820 is configured to change a format of dataprovided on the output plus 2706A and output minus 2706B lines from thecircuitry 2702 to a format compatible with another component, such as acomponent provided in the first and/or second circuitry housings 606Aand 606B, and/or the external power unit 2602.

FIG. 29 illustrates generally an example of an elongated implantabledevice 2900. The device 2900 is similar to the device 2500 describedabove in the example of FIG. 25, however the device 2900 includes asingle circuitry housing 606C. That is, the device 2900 does not includethe elongated portion 2502 from the example of FIG. 25. Instead, thedevice 2900 includes the various implantable device circuitry (see,e.g., circuitry 2702 of FIG. 27 and circuitry 2802 of FIG. 28) in thesingle circuitry housing 606C.

In the example of FIG. 29, the device 2900 includes the frustoconicalconnector 2504, such as connected between the body portion 602 and thesingle circuitry housing 606C. Differently dimensioned embodiments ofthe frustoconical connector 2504 can be used to provide differentlydimensioned devices, such as with respect to the circuitry housingsand/or distal lead sections (e.g., the body portion 602 and electrodes604) of the devices. In an example, the frustoconical connector 2504 isconfigured to aid implant procedures, such as by helping to graduallywiden an incision as the device is inserted, which in turn can help toreduce patient discomfort.

C. Injectable and/or Nerve-Wrapping Implantable Assemblies

Various embodiments described herein include electrode systemsdeployable inside of a patient body, such as at a neural target forelectrostimulation therapy delivery. In an example, an implantableelectrode system can include an elongated assembly body configured tohouse electrostimulation circuitry or sense circuitry, and an electrodeassembly coupled to the electrostimulation circuitry or sense circuitryand configured to provide electrostimulation to, or sense electricalsignal activity from, the neural target inside of the patient body. Inan example, the electrode assembly includes multiple elongate membersthat extend away from the assembly body in a predominately longitudinaldirection. The electrode assembly can have a retracted firstconfiguration when the electrode assembly is inside of a deploymentsheath or cannula, and an expanded second configuration when theelectrode assembly is outside of the cannula. In an example, anelectrode assembly can include a further expanded third configuration inwhich the electrode assembly receives or encloses a neural target. Aneural target can include a nerve, or other tissue such as a vein,connective tissue, or other tissue that includes one or more neuronswithin or near the tissue.

In an example, an electrode having a cuff configuration can be used tosurround all or a portion of a nerve, such as to provide anelectrostimulation therapy to the nerve using the electrode. Such a cuffelectrode can be positioned near, or attached to, the nerve usingvarious techniques. For example, a cuff electrode can be tied around anerve using sutures. Such tying can require two-handed manipulation andcan be tedious and difficult for a clinician to install.

In an example, a cuff electrode can have a helical shape. Such a helicalcuff electrode can be wrapped around a nerve to install it. Relative toa tied cuff electrode, a relatively long length or section of a nervesegment is used with a helical cuff electrode because of the way thenerve is wrapped by the helical structure. Accordingly, a relativelylong length of nerve must be dissected to provide access for theelectrode, which can potentially cause nerve damage if installation isimproper.

Implantation of tied or helical cuff electrodes is typically performedusing two-handed installation techniques and open surgery. Although somesuturing can be performed laparoscopically, such a procedure can betedious, difficult, and invasive. Furthermore, cuff electrodes can betoo large to insert by injection or using laparoscopic tools, andaccordingly other surgical openings can be required.

Cuff electrodes can be manufactured in different sizes, and theclinician or installer can select an appropriately sized electrode atthe time of implant, such as based on intra-operative measurement of adestination nerve. This adds time and complexity to an installationoperation.

In addition to addressing the problems above, there is an ongoing desireto reduce a displacement volume of implantable neural stimulation, orneuro stimulation, devices. Miniaturization of such devices can allowfor an easier and less invasive implant procedure, reduce a surface areaof the implantable device which can in turn reduce a probability of apost-implant infection, and can help ensure long-term patient comfort.

In an example, solutions to the various problems associated withtraditional cuff electrodes can be addressed using injectablenerve-wrapping electrodes. In an example, such a nerve-wrappingelectrode can be leadless, and can be wirelessly coupled with one ormore other devices using midfield wireless communication techniques,such as to transfer power or data. Midfield powering technology,including transmitters, transceivers, implantable devices, circuitry,and other details are discussed generally herein at FIGS. 1-5.

In an example, a nerve-wrapping electrode can address the variousproblems described above, among others, by including or using one ormore of an improved attachment mechanism that responds to a forceapplied in at least one direction, includes electrodes that areexpandable and retractable, and can be installable in a patient body ata target location using an injectable sheath or cannula. In an example,various portions of the nerve-wrapping electrode can be elastic orflexible to conform to a variety of body structures or target locationphysiologies.

In an example, a folded, deformable, or conformable electrode assemblycan be pushed through a sheath and then deployed at a target location ina body at or near a nerve site. The electrode assembly, or an electrodeitself, can have an elastic or spring quality that causes the electrodeassembly, or causes another portion of the assembly appurtenant to oneor more electrodes, to expand when it is deployed outside of theinstallation sheath. In other examples, the electrode assembly and/orelectrode itself need not splay or flex to accommodate a neural targetsuch as when the target is sufficiently narrow or the electrode(s) aresufficiently open to receive the target.

In an example, a non-deployed electrode can have a length characteristicthat is related to its diameter when the electrode is deployed. Forexample, a longer electrode can have a larger deployed diameter than ashorter electrode. In this manner, a deployed electrode structure canhave a relatively larger diameter in some respects than the diameter ofa sheath used to deploy the electrode structure.

In an example, a nerve can be disposed at or around an artery or tendon.In such cases, a large diameter cuff can be used to sufficientlysurround the nerve and its surrounding tissue. Using the deployablenerve-wrapping electrode, the large diameter can be attained withoutusing open surgery to install a large traditional cuff or helicalelectrode.

In an example, a nerve-wrapping electrode remains flexible, orexpandable and retractable, such as after installation. Therefore, thenerve-wrapping electrode may not constrict a pulsating artery. In someexamples, however, if a nerve-wrapping electrode is too loose or tooeasily expanded, then the electrode may not provide optimal surface areacontact with the target tissue, and therefore it may use more orvariable power to elicit the same response from a target.

In an example, two or more electrodes can be delivered concurrentlyusing the same sheath, according to various embodiments describedherein. For example, the two or more electrodes can be arranged inparallel such that they are provided in a side-by-side manner about atarget nerve. The electrodes can be placed in a variety ofconfigurations to stimulate across the target transversely or axially.In an example, the multiple electrodes can be used for electricalblocking or electrical activity sensing and recording. In an example,the electrodes, or portions of the same electrode, can be aligned suchthat distal portions of the electrodes are, or can be made to be,touching. In other examples, the electrodes can be offset from oneanother such that their distal portions do not touch in compressed or inuncompressed configurations.

In an example, the nerve-wrapping electrode can be integrated with apower transfer system (e.g., a wireless power transfer system) andelectronics, or it can be lead-based.

In an example, the nerve-wrapping electrode can be a part of anelectrode deployment system that includes a joint configured to arrangethe electrode's drive assembly parallel to the nerve.

These and other features of the various implantable devices andelectrode configurations are discussed herein with reference to variousfigures. Various combinations of the embodiments shown are alsocontemplated by the present inventors.

In an example, the circuitry housing 606 (see, e.g., FIG. 6, or otherembodiments of the circuitry housing discussed herein) can includeelectric or electronic components for providing stimulation to thepatient in which the implantable device is implanted. Also, aspreviously discussed, the circuitry housing can include one or morefeedthroughs such as to seal the circuitry housing 606 and/or provideelectrical signals from within the circuitry housing 606 to othercircuitry external to the housing. The feedthroughs can have a minimalsurface area to help reduce a volume of the implantable device.Miniaturizing the feedthroughs, however, can be quite challenging. Forexample, problems can be realized in forming a plate with feedthroughswhere the plate includes a diameter that is less than 3 millimeters. Thematerials and process used in creating the feedthroughs and/or housingassemblies can be important in creating such a miniaturized cap, such asdescribed herein.

By reducing the diameter of the feedthroughs and housing end caps, theimplantable device can require or use a relatively smaller opening in apatient than for previous implantable devices. A cannula or sheath(e.g., including a lumen through which the implantable device isinserted into a patient) can be made with a smaller diameter as well. Insome examples, the implantable device can be sufficiently small to allowan implant procedure without a cannula. In one or more examples, a bodyportion 602 that includes electrodes (e.g., ring electrodes) situatedthereon can be replaced with respective electrodes on or in thecircuitry housing 606 and/or on one or more end caps for the housing.Such a configuration can reduce an overall length of the implantabledevice, reduce displacement volume of the implantable device, reducerisk of implant infection, and/or reduce a cost of manufacture for theimplantable device.

In an example, one or more electrodes can extend from the circuitryhousing 606 and/or from the body portion 602 of the implantable device600. Although reference is made in this and other discussions herein tothe implantable device 600, other embodiments of the implantable device,such as discussed elsewhere herein, can similarly be used. Theelectrodes can extend away from the body portion 602 substantially inthe direction of the longitudinal axis of the body portion 602 (such asrather than transversely to the body portion 602). Thelongitudinally-extending electrodes can thus be used without impedingthe device from traveling or sliding through a cannula for delivery to aneural target.

FIGS. 30A and 30B illustrate generally different views of an example3000 of an implantable electrode assembly 3001 inside of a cannula 3010.The implantable electrode assembly 3001 includes a body portion 3002 andan electrode portion 3003. The electrode portion 3003 includes one ormore discrete electrodes that extend in the direction of a longitudinalaxis of the cannula 3010 away from the body portion 3002 of theimplantable electrode assembly 3001.

In an example, the electrode portion 3003 includes multiple electrodes.At least one of the electrodes can be flexible. In an example, theelectrode portion 3003 is configured to receive and retain a neuraltarget (e.g., a nerve, or a nerve bundle) or other biological tissuetarget. FIG. 30B illustrates generally a perspective view of the example3000, including the electrode portion 3003 inside of the cannula 3010.

In an example, the electrode portion 3003 is compressed inside of thecannula. When the electrode portion 3003 is compressed, extensionmembers of the electrode portion 3003 are elongated and can be held inthe compressed configuration such as by the inner side walls of thecannula 3010.

FIG. 30C illustrates generally an example of the implantable electrodeassembly 3001 partially outside of the cannula 3010. In the example ofFIG. 30C, the electrode portion 3003 is uncompressed, or extended. Whenthe electrode portion 3003 exits the cannula, a retention force (such asprovided by the side walls of the cannula 3010) acting on the extensionmembers of the electrode portion 3003 is removed, and the extensionmembers can expand or recoil away from each other. That is, theextension members can extend transversely away from the longitudinalaxis of the cannula 3010 when the electrode portion 3003 is unencumberedby the walls of the cannula 3010.

FIG. 30D illustrates generally an example of the implantable electrodeassembly 3001 deployed from the cannula 3010 and coupled to a push rod3020. In an example, a proximal end of the implantable electrodeassembly 3001 is configured to receive the push rod 3020, and the pushrod 3020 urges the implantable electrode assembly 3001 down a lumen ofthe cannula 3010.

FIG. 30E illustrates generally an example of the implantable electrodeassembly 3001 including an intermediate lead 3050. In the example ofFIG. 30E, the electrode portion 3003 can be coupled to the body portion3002 by way of an intermediate lead 3050 that includes electricalconductors that couple drive circuitry in the body portion 3002 with oneor more discrete electrodes in the electrode portion 3003. In anexample, the body portion 3002 can include, use, or be configuredsimilarly to the circuitry housing 606 (such as including one or more ofthe first circuitry housing 606A, the second circuitry housing 606B, thesingle circuitry housing 606C, etc.).

FIG. 31A illustrates generally a first example 3110 of the implantableelectrode assembly 3001 approaching a first neural target 3115. In theexample of FIG. 31A, the electrode portion 3003 is shown in a firstextended configuration (e.g., outside of a delivery cannula) wherein atleast some part(s) of the extension members of the electrode portion3003 are spaced apart by a greater distance relative to a compressedconfiguration. In the example of FIG. 31A, a first force acts in a firstdirection 3101 on the implantable electrode assembly 3001, such as bythe push rod 3020.

FIG. 31B illustrates generally a second example 3120 of the implantableelectrode assembly 3001 with nerve-wrapping electrodes flexing away fromthe first neural target 3115. In FIG. 31B, the implantable electrodeassembly 3001 is adjacent to, and the outer distal edge of the electrodeportion 3003 impinges on, the first neural target 3115. In response tothe first force continuing to act in the first direction 3101, theextension members of the electrode portion 3003 can be driven or pushedapart such that the first neural target 3115 can be engaged, received,or accepted between the extension members. That is, a second force canact in a second direction 3102 when the electrode portion 3003 is drivenagainst the first neural target 3115.

FIG. 31C illustrates generally a third example 3130 of the implantableelectrode assembly 3001 with nerve-wrapping electrodes provided aboutthe first neural target 3115. In the example of FIG. 31C, the electrodeportion 3003 grasps and retains the first neural target 3115. A springforce or retention force acts in a third direction 3103 (e.g.,substantially oppositely to the second direction 3102) to push orretract the extension members of the electrode portion 3003 backtogether, or toward one another, such as toward the first extendedconfiguration shown in FIG. 31A.

FIGS. 32A, 32B, and 32C illustrate generally examples of using adifferent flexible electrode configuration to receive and retain asecond neural target 3215. The second neural target 3215 can be the sameor different neural target than the first neural target 3115. Theexample of FIG. 32A illustrates generally an example 3210 of animplantable electrode assembly with a hook-shaped nerve-wrappingelectrode assembly 3253 adjacent to the second neural target 3215.

FIG. 32B illustrates an example 3220 with the implantable electrodeassembly with the hook-shaped nerve-wrapping electrode assembly 3253flexing away from the neural target 3215 to provide access to a neuraltarget retention region 3260 that is encircled or enclosed at least inpart by the electrode assembly 3253. That is, a distal or end portion ofthe hook-shaped nerve-wrapping electrode assembly 3253 can flex,stretch, or otherwise extend to expose the retention region 3260 tothereby receive the second neural target 3215 therein. FIG. 32Cillustrates generally an example 3230 of the electrode assembly withhook-shaped nerve-wrapping electrode assembly 3253 provided about thesecond neural target 3215, that is, with the second neural target 3215seated in the nerve retention region 3260.

FIGS. 33A and 33B illustrate generally side and perspective views,respectively, of a second implantable electrode assembly 3301. Thesecond implantable electrode assembly 3301 includes a distal portionhaving second nerve-wrapping electrodes 3303 and an electrode insulatormember 3305. In an example, the second nerve-wrapping electrodes 3303includes one or more discrete electrodes that extend in the direction ofa longitudinal axis of the second implantable electrode assembly 3301.At least one of the electrodes can be flexible, and the electrodes canbe configured to receive and retain a neural target (e.g., a nerve, or anerve bundle) or other biological tissue target.

The electrode insulator member 3305 is configured to electricallyisolate the electrodes from surrounding, non-targeted tissue at or nearan implantation site. In an example, the electrode insulator member 3305is made at least in part from silicone or from another non-conductiveand biocompatible material. In an example, the electrode insulatormember 3305 is flexible and can be conformable to a shape or extensionconfiguration of the electrodes that it surrounds. In an example, theelectrode insulator member 3305 includes a slit through which a neuraltarget is configured to reside when the second implantable electrodeassembly 3301 is installed about the target. The electrode insulatormember 3305 can be used with any electrode embodiment discussed herein,or the member can be unused. In an example, the electrode insulatormember 3305 can help prevent damage to, or signal interference from,nearby tissue.

FIG. 34 illustrates generally an example of another embodiment ofnerve-wrapping electrodes 3413 and the electrode insulator member 3305.In the example of FIG. 34, the nerve-wrapping electrodes 3413 include aninwardly-facing hook-shaped distal portion that can be helpful forretaining a target tissue when the assembly is installed in a patient.The examples of FIGS. 33A and 33B include the nerve-wrapping electrodes3303 which can include an outwardly-facing hook-shaped distal portionthat can include a gap or spacing to help facilitate coupling with atissue target, such as a larger-diameter neural target.

FIGS. 35A and 35B illustrate generally side and perspective views,respectively, of a third implantable electrode assembly 3501. The thirdimplantable electrode assembly includes a third embodiment ofnerve-wrapping electrodes 3503. The third embodiment of nerve-wrappingelectrodes 3503 can include a pair of flexible, elongate conductors, andeach conductor can extend away from a body portion of the assembly 3501in a longitudinal direction of the body portion. In an example, eachconductor terminates, at its distal end, in a bulbous end portion. Theconductors can be flexible and can include a turned or bent portion. Inan example, each of the conductors turns or bends toward a longitudinalaxis of the body, and/or toward the other one of the conductors. In anexample, the conductors turn or extend substantially along a helicalpath, and the third implantable electrode assembly 3501 is configuredfor installation by turning or twisting the assembly about a neuraltarget to seat the neural target between the conductors.

Various other implantable electrode assembly configurations cansimilarly be used or applied, such as using the same or similarcannula-based delivery system as described above in the examples ofFIGS. 30A-35B, and such as using the cannula 3010. For example, FIG. 36illustrates generally a fourth implantable electrode 3600. The fourthimplantable electrode 3600 can be used together with a body portion(e.g., the body portion 3002) of an implantable assembly. The example ofthe fourth implantable electrode 3600 includes a pair of hook-shapedelectrode members. The members can be adjacent or offset from oneanother, and in some examples one or more of the members can be flexibleor configured to move relative to one another, such as to facilitatereception of a neural target between the members.

FIG. 37 illustrates generally a fifth implantable electrode 3700. Thefifth implantable electrode 3700 can be used together with a bodyportion (e.g., the body portion 3002) of an implantable assembly. Theexample of the fifth implantable electrode 3700 includes a pair ofhook-shaped electrode members with bulbous end features. The members canbe adjacent or offset from one another, and in some examples one or moreof the members can be flexible or configured to move relative to oneanother, such as to facilitate reception of a neural target between themembers.

FIG. 38 illustrates generally an example 3800 of an implantableelectrode assembly 3801 configured to deliver an electrostimulationaxially to a neural target 3815. In the example 3800, the implantableelectrode assembly 3801 includes first and second electrodes 3600A and3600B that are axially spaced apart along a longitudinal axis of theneural target 3815. In an example, the first and second electrodes 3600Aand 3600B include respective instances of the fourth implantableelectrode 3600 discussed above, such as coupled to a cannula-deliveredbody portion 3002 of an implantable device. The first and secondelectrodes 3600A and 3600B can be separately or individually addressableby drive circuitry (see, e.g., the stimulation driver 2814 in theexample of FIG. 28) in a housing of the implantable electrode assembly3801. In an example, one of the first and second electrodes 3600A and3600B is configured as an anode and the other is configured as a cathodefor use in providing an electrostimulation therapy to the neural target3815.

FIG. 39 illustrates generally an example 3900 of an implantableelectrode assembly 3901 configured to deliver an electrostimulationtransversely to a neural target 3915. In the example 3900, theimplantable electrode assembly 3901 includes first and second electrodes3911 and 3912 that are spaced apart from each other. In the illustratedinstalled configuration, the first and second electrodes 3911 and 3912are provided adjacent to opposite sides of the neural target 3915. Thefirst and second electrodes 3911 and 3912 can be separately orindividually addressable by drive circuitry (see, e.g., the stimulationdriver 2814 in the example of FIG. 28) in the housing of the implantableelectrode assembly 3901. In an example, one of the first and secondelectrodes 3911 and 3912 is configured as an anode and the otherelectrode is configured as a cathode for use in providing anelectrostimulation therapy to the neural target 3915.

FIG. 40 illustrates generally an example 4000 of an implantableelectrode assembly 4001 with a flexible body. That is, one or moreportions of the electrode assembly 4001 can include a portion that canflex, bend, fold, turn, stretch, or otherwise conform to differentpositions. At least a body portion 4002 can thus be arranged or providedsubstantially parallel to a neural target 4015. In the example 4000, theimplantable electrode assembly 4001 includes a distal electrode portion4003, such as comprising one or more electrodes, that can be wrappedabout the neural target 4015. In an example, the body portion 4002 ofthe implantable electrode assembly 4001 includes a can electrode orhousing electrode configurable as an anode or cathode, and the distalelectrode portion 4003 includes at least one electrode configurable asthe other of an anode or cathode.

In an example, the electrode assembly 4001 includes a flexible joint inits body portion 4002 such that, after deployment of the distalelectrode portion 4003 at or about the neural target 4015, at least aportion of the elongated body portion 4002 can be situated or providedsubstantially parallel to a longitudinal axis of the neural target. Inthe example of FIG. 40, the electrode portion 4003 includes two pairs ofelongate members with respective conductive portions, and a first one ofthe pairs can be configured as an anode and a second one of the pairscan be configured as a cathode. In this example, the electrode assembly4001 can be configured to deliver an electrostimulation therapy signalto the neural target 4015 when the pairs are coupled to the neuraltarget 4015 and spaced apart along the neural target 4015 in an axialdirection of the neural target 4015.

FIG. 41 illustrates generally an example of a method 4100 that includesaccessing a neural target and providing an electrode about the neuraltarget. At operation 4110, the example includes accessing a neuraltarget inside of a patient body using a surgical apparatus, such asincluding using a cannula and a nerve-wrapping electrode assembly thatcan slide from a proximal end to a distal end of a lumen inside of thecannula. Operation 4110 can include using one or more of the electrodeassemblies or embodiments as illustrated in the examples of FIGS.30A-40.

At operation 4120, the nerve-wrapping electrode assembly can be deployedfrom the cannula. In an example, an electrode assembly can be deployedusing a push rod to slide or force the nerve-wrapping electrode assemblyoutside of the cannula. For example, FIG. 30A illustrates generally anexample that includes an implantable electrode assembly 3001 inside of acannula 3010. FIGS. 30C and 30D illustrate the implantable electrodeassembly 3001 partially and fully deployed from the cannula 3010,respectively. At operation 4130, the example includes expanding theelectrode members of the of nerve-wrapping electrode assembly to anexpanded second configuration. For example, as shown in FIG. 30E, whenthe electrode portion 3003 is deployed and unencumbered by the sidewallsof the cannula 3010, the electrode portion 3003 can include one or moremembers that can be extended or deployed away from one another, such asto provide a retention region for a neural target between the members.

At operation 4140, the example includes positioning a distal end of theelectrode members of the nerve-wrapping electrode assembly adjacent to aneural target. In an example, the assembly can be provided substantiallytransverse to a longitudinal axis of the neural target (see, e.g., FIG.31A). In an example, the assembly can be provided substantially parallelto a longitudinal axis of the neural target, such as for embodimentsthat require or use a twisting or turning motion to seat the neuraltarget between different portions of one or more conductors.

At operation 4150, the example includes pushing the nerve-wrappingelectrode assembly toward the neural target to thereby further expandthe electrode members of the nerve-wrapping electrode assembly andreceive the neural target between the electrode members. An illustrationof operation 4150 can be found at FIG. 31B. At operation 4160, themethod 4100 can include retaining the neural target between theelectrode members (see, e.g., FIGS. 31C, 32C, and 38-40). At operation4170, electrical activity sensing or electrostimulation therapy deliverycan be performed using the electrode members.

D. Vascular Deployments

Solutions to the various problems discussed herein and associated withtraditional electrodes and implant procedures can be addressed usingminiature or injectable electrodes and electrode assemblies. In anexample, such an electrode assembly can be leadless, and can bewirelessly coupled with one or more other devices using midfieldwireless communication techniques, such as to transfer power or data.Midfield powering technology, including transmitters, transceivers,implantable devices, circuitry, and other details are discussedgenerally herein at FIGS. 1-5.

Various advantages come with midfield-powered devices. For example, awirelessly-powered device does not require implantation of a relativelylarge, battery-powered pulse generator and the leads that are requiredto connect it electrically to the stimulation electrodes. This enables asimpler implant procedure at a lower cost and a much lower risk ofchronic infection and other complications. A second advantage includesthat the battery power source can be external to the patient and thustraditional design constraints (e.g., ultra-low power and ultra-highcircuit efficiency requirements) can be less critical. Third, a midfieldelectrode device can be substantially smaller than traditional devices.Smaller devices can be better tolerated by and more comfortable topatients. In some examples, midfield devices can also be less costly tomanufacture and implant or install inside of a patient.

In an example, a midfield device can be implanted or installed andconfigured to deliver electrostimulation to a renal nerve target. In anexample, the midfield device can be implanted or installed at leastpartially in the vascular system of a patient. For example, the midfielddevice can be implanted or installed in an artery, vein, or other bloodvessel. In an example, a midfield device can be implanted or installedin a jugular vein and configured to deliver electrostimulation to avagal nerve target. Examples of various implantable deviceconfigurations are discussed below.

In an example, a midfield-based implantable device can be used todeliver electrostimulation therapy to renal targets. In recent years,there has been a significant amount of pre-clinical and clinicalinvestigation into the denervation of the renal nerves to modulate bloodpressure in the treatment hypertension. The size of the hypertensionpatient population is significant and there is a subset of that patientpopulation that are refractory or non-responsive to conventional medicalmanagement including pharmaceuticals such as diuretics, ace inhibitorsand other stronger pharmaceutical agents that are intended to lowerblood pressure.

Although an acute procedure known as renal denervation showed promise inearly clinical studies in reducing systolic and diastolic bloodpressures in these refractory uncontrolled patients, the presentinventors have recognized that a clinical need remains for a medicaldevice that can treat patients with hypertension. In an example, analternative to denervation can include providing electrostimulation torenal nerve targets, such as using neuromodulation techniques. In anexample, such electrostimulation can be delivered through the largerenal arteries with an implantable electrostimulator. Other, non-renaltissue areas can be similarly targeted.

The renal nerves are part of the sympathetic nervous system. In anexample, neuromodulation (e.g., delivery of electrostimulation therapy)at the renal nerves can result in a similar effect that is achieved inthe acute renal denervation procedure. In an example, such renalelectrostimulation can be used in the treatment of uncontrolledhypertension. Other potential therapeutic benefits include themodulation of sympathetic-parasympathetic balance and modulation of theinflammatory response which is central in several serious diseasesincluding heart failure and inflammatory bowel syndrome.

In an example, systems and methods according to the present disclosurecan include or use a midfield-powered device that is implanted,installed, fixated, coupled, or otherwise disposed in a renal (or other)artery or other portion of a patient's vasculature. The device can bepowered by an external powering unit that can be located at or near thekidney region where the stimulation device is implanted (see, e.g.,discussion of FIGS. 1-5 regarding power transmission from an externalunit to an implanted device).

In an example, a therapy signal delivered by the implanted midfielddevice can create an electrical field that emanates from the artery andtravels through the artery wall to the renal nerve(s) (or other neuraltarget) located nearby. In an example, the implanted midfield device canbe implanted using tools that are substantially the same or similar totools used in balloon catheter angioplasty, as discussed above. In anexample, a proximal end of the device includes a fixation mechanism thatis deployed at implant and is configured to minimally impede and notblock blood flow through the artery. The fixation mechanism can havevaried and different configurations, some of which are described herein.

FIG. 42 illustrates generally an example 4200 of an implant location fora midfield device 4210 with respect to vasculature in the torso. In anexample, an implant procedure can begin with an introduction of adelivery catheter or cannula through the Right Femoral Artery and to theRight External Iliac Artery 4221. The dashed line in FIG. 42 shows apath by which the midfield device 4210 can be introduced and locatedinto position near or in the renal artery 4222. Other paths ordestination locations can similarly be reached by the midfield device.

FIG. 43 illustrates generally an example that includes side andcross-section views of a midfield device 4310 configured forinstallation and fixation inside a blood vessel. Fixation of the devicecan be important to secure its chronic positioning for optimal nervestimulation (e.g., at a renal target or elsewhere) and to allowsubstantially unrestricted blood flow through the vessel. In an example,the midfield device 4310 is 7 French (2.33 mm) or less at its largestdiameter on the proximal end. Devices with other dimensions cansimilarly be used.

In an example, the implantable device does not block blood flow throughthe vessel when deployed because the vessel's inner diameter is largerthan a cross-sectional area of the midfield device 4310 itself. Themeasured mean diameter of an artery can differ depending on the imagingmethod used. In an example, a representative diameter was found to be5.04±0.74 mm using ultrasound, but 5.68±1.19 mm using angiography.

At right in the example of FIG. 43, the midfield device 4310 is deployedand affixed inside a first vessel having vessel wall 4301. The locationof the midfield device 4310 can be near or adjacent to a renal nerve4302 or other neural target. In an example, the midfield device 4310includes a proximal housing assembly 4306 and a distal electrodeassembly 4304. Drive circuitry (see, e.g., the stimulation driver 2814in the example of FIG. 28), such as inside the proximal housing assembly4306, can be used to provide electrical signals that drive the electrodeassembly 4304 to provide an electrostimulation field 4303, and suchfield can be configured to influence or affect activity at the neuraltarget.

In the example of FIG. 43, the midfield device 4310 includes variousfixation features 4316. For example, the midfield device 4310 as showncan include multiple tines that extend away from the device's bodyportion, and the tines impinge on the inner surface of the vessel wall4301 to locate and affix the device relative to the vessel, such ascoaxially with the vessel. At least a portion of the midfield device4310 is spaced apart from the vessel wall 4301 by the tines or fixationfeatures 4316 such that one or more regions 4307 of unrestricted bloodflow exist around the midfield device 4310. Although the example of FIG.43 shows four discrete tines as the fixation features 4316, additionalor fewer tines can be used as long as the number of tines is sufficientto affix the midfield device 4310 in a specified location relative tothe vessel.

FIGS. 44-47 illustrate generally partial views of examples of differentembodiments of the fixation features 4316 as applied to the midfielddevice 4310. FIG. 44 illustrates generally a first example 4400 of amidfield device with multiple passive elements 4416 that projectlaterally away from the midfield device's housing assembly 4306. Thepassive elements 4416 can comprise silicone or other non-reactivematerial, and can be configured to hold the implantable midfield device4310 in position with respect to the vessel wall 4301. In an example,the passive elements 4416 provide a friction-fit with the vessel wall4301 at a location where an inner diameter of the vessel becomes smallenough, or tapers, to create an interference fit. In other words, anouter dimension of the passive elements 4416 can be about the same asthe vessel inner cross-section dimension (e.g., at a location where thevessel tapers), while the body of the midfield device 4310 (e.g.,comprising one or more electrodes) has a smaller outer dimension so asnot to restrict blood flow around the device.

FIG. 45 illustrates generally a second example 4500 of a midfield devicewith multiple inflatable elements 4516 that project laterally away fromthe midfield device's housing assembly 4306. The inflatable elements4516 can include one or more inflatable balloons (e.g., using gas or aliquid) that are configured to hold the implantable midfield device 4310in position with respect to the vessel wall 4301, such as when inflatedto an inner diameter of the vessel wall 4301 and thereby providing aninterference fit. In an example, total occlusion of the vessel by, e.g.,the inflatable elements 4516, can be acceptable under somecircumstances. For example, occlusion of some small veins can betolerated, or temporary occlusion can be permitted during placementprocedures, such as for intraoperative testing.

FIG. 46 illustrates generally a third example 4600 of a midfield devicewith multiple active elements 4616 that project laterally away from themidfield device's housing assembly 4306. In an example, the activeelements 4616 include one or more spring-loaded elements that can bedeployed by the implanting clinician at the time of the implantprocedure. In an example, the active elements 4616 can be retracted orconstrained to a minimal diameter as the device is inserted orimplanted. Once located in position, the clinician can deploy the activeelements 4616 (e.g., using a mechanism on the cannula or push rod) andcause the active elements 4616 to expand to the inner diameter of thevessel wall 4301 thereby providing an interference fit and fixating themidfield device 4310 in a specified location.

FIG. 47 illustrates generally a fourth example 4700 of a midfield devicewith a fixation element 4716 that projects laterally away from themidfield device's housing assembly 4306. The fixation elements 4716 canbe configured to hold the implantable midfield device 4310 in positionagainst the vessel wall 4301. That is, while the examples of FIGS. 43-46generally show fixation elements that are configured to locate themidfield device 4310 centrally or coaxially with respect to the vessel,the fourth example 4700 is configured to be offset from the center oraxis of the vessel. That is, the fourth example 4700 includes a fixationelement 4716 that biases the midfield device's housing assembly 4306toward one side of the blood vessel. Similar to the other embodiments,however, the fourth example 4700 has a smaller outer dimension than thevessel wall 4301 so as not to restrict blood flow around the device.

FIG. 48 illustrates generally a variation of the example device 4310from FIG. 43. In the example 4800 of FIG. 48, at least one of thefixation features 4316 includes an electrode 4801 that is configured topenetrate the vessel wall 4301. That is, in an example, the electrode4801 is integrated with one or more of the fixation features 4316. Inanother example, the electrode 4801 is a discrete electrode that isseparate from the fixation features 4316. The electrode 4801 can bedeployable after the device is located in position in the arterialsystem. In an example, the electrode 4801 includes a portion of anelectrode array (e.g., a radially-extending array) provided along aportion of the midfield device 4310.

In an example, various other embodiments can include stent-based and/orspring-based systems for locating a midfield device inside a vessel.Such embodiments can have a low profile, can be constructed usingbiocompatible materials, and can be compatible with existingcatheter-based tools and techniques.

FIG. 49 illustrates generally an example of a stent-based system 4900that can include a midfield device 4910 coupled to an expandablescaffold 4902. Although illustrated schematically in the figure by arectangle, the midfield device 4910 can have any suitable size and shapefor deployment inside a vessel. Generally, an outer hermetic housing ofthe midfield device 4910 has a minimal or low profile to minimizeobstruction of fluid flow around or over the device, as describedelsewhere herein.

The midfield device 4910 includes, or is coupled to, an antenna toreceive midfield signals, such as from another implant or from a deviceprovided externally to the patient. The midfield device 4910 can furtherinclude an energy storage element, and one or more sensors (e.g., tosense a physiologic characteristic from within the vasculature) orelectrodes (e.g., to provide an electrostimulation therapy from within,or at least partially within, the vasculature).

The system 4900 can be configured for delivery to an intravascularlocation using a cannula. That is, the expandable scaffold 4902 andmidfield device 4910 can be configured to be pushed through a lumen of acannula toward a distal open end of the cannula for installation insideof a vessel. After exiting the lumen, the system 4900 can be expanded,using the expandable scaffold 4902, to thereby hold the midfield device4910 inside of the vessel, and preferably toward one side wall of thevessel, to reduce obstruction of flow through the vessel. In an example,the delivery system includes or uses a balloon 4903 to expand thescaffold 4902 after deployment from the cannula.

In an example, the expandable scaffold 4902 comprises a spring materialor spring construction. In this example, the scaffold 4902 is contractedor compressed inside of the delivery lumen of the cannula but thescaffold 4902 recoils or expands automatically, such as due to shapememory of the material, upon deployment from the lumen.

FIGS. 50-52 illustrate generally examples of stent-based or spring-basedsystems that can include or use a midfield device 5010. In the exampleof FIG. 50, the midfield device 5010 is coupled to a first springsupport 5002. The first spring support 5002 can include at least oneelongate member have a curved or wave-type shape. The midfield device5010 can be coupled at various locations along the elongate member. Inthe example of FIG. 50, the midfield device 5010 is coupled at asubstantially central location of the elongate member, such as near oneof the member's maximum (or minimum) extents.

At left in FIG. 50, the first spring support 5002 is illustrated insideof a cannula 5020, and at right, FIG. 50 shows the first spring support5002 deployed outside of the cannula 5020. The first spring support 5002is compressed or contracted before deployment when it is inside of thecannula 5020. After deployment from a distal end of the cannula 5020into a vessel, e.g., by a clinician using a push rod to slide the firstspring support 5002 through the lumen of the cannula 5020, the firstspring support 5002 can expand inside of the vessel and thereby forcethe midfield device 5010 toward or against a sidewall of the vessel.Placing the midfield device 5010 toward one sidewall of the vessel canhelp minimize restriction of blood flow through the vessel, and can helpreduce blood flow turbulence around the device.

FIGS. 51 and 52 illustrate generally other examples of spring-basedsupport members coupled to the same or different midfield device 5010.Like the example of FIG. 50, second and third spring-based supports 5102and 5202 in FIGS. 51 and 52, respectively, can be compressed during adeployment procedure, such as when each member is disposed inside of thecannula 5020, and can be expanded after deployment from a deliverycannula.

In the example of FIG. 51, the second spring-based support 5102 includesat least one elongate member have a coil shape. The midfield device 5010can be coupled at various locations along the elongate member. In theexample of FIG. 51, the midfield device 5010 is coupled at asubstantially central location of the elongate member.

In the example of FIG. 52, the third spring-based support 5202 includesa pair of wire members arranged to form an elongated, compressibleoval-shaped assembly. The midfield device 5010 can be coupled at variouslocations along the assembly. In the example of FIG. 52, the midfielddevice 5010 is coupled at a substantially central location of theassembly such that the device is pushed toward one sidewall of thevessel when the third spring-based support 5202 expands inside of avessel.

FIG. 53 illustrates generally an example of a fourth spring-basedsupport 5302 that includes an elongate member having a coil shape. Inthe example of FIG. 53, a midfield device 5310 is coupled to the support5302. In an example, the midfield device 5310 includes or is coupled toa portion of the support 5302 that comprises a portion of an antenna5312 for the midfield device 5310. That is, the antenna 5312 for themidfield device 5310 can be integrated with the support 5302, or formedat least in part from the same material as the support 5302. In anexample, the midfield device 5310 includes integrated electrodes orsensors, and in other examples, one or more electrodes or sensors iscoupled to, and located remotely from, a main housing of the midfielddevice 5310. In the example of FIG. 53, the midfield device 5310includes first and second electrodes 5321 and 5322 coupled to thesupport 5302 and spaced apart from the main housing of the midfielddevice 5310. The electrodes can be provided in fixed locations along thesupport 5302 or, in some examples, their positions can be adjusted by aclinician such as before or during implantation in a vessel.

In an example, a method of using the midfield device 5310 includesreceiving energy at the midfield device 5310 using the antenna 5312. Atleast a portion of the received energy can be used in anelectrostimulation therapy provided using the first and secondelectrodes 5321 and 5322. In an example, one or more physiologic sensorscan be coupled to the midfield device 5310, and at least a portion ofthe received energy can be used to power the sensor(s) and/or to processinformation from the sensor(s) and/or to transmit information from thesensor(s) to a remote device, such as to another implant or to anexternal device.

In the examples of at least FIGS. 50-53, at least some portion of therespective support members can have a helical shape configured toencourage the support members to reside near or against a vessel wallwhen the device is deployed. Providing the support members against avessel wall can help promote endothelialization and minimize blood flowobstruction.

FIG. 54 illustrates generally an example of a system 5400 that caninclude multiple structures that are each configured for intravascularplacement during a single implant procedure. The system 5400 includes adistal structure 5401 and a proximal structure 5402, and each of thedistal and proximal structures 5401 and 5402 can be deployed using acommon cannula 5410. In an example, the distal and proximal structures5401 and 5402 are coupled to a common push rod. In the example of FIG.54, the distal and proximal structures 5401 and 5402 are coupled torespective first and second push rods 5411 and 5412. In an example, eachof the distal and proximal structures 5401 and 5402 includes arespective deployment device, such as a balloon.

In an example, the distal and proximal structures 5401 and 5402 arecommunicatively coupled, such as to provide a transmission channel forone or both of power and data between the structures. In the example ofFIG. 54, the structures are coupled using a conductive lead 5430. In anexample, the distal and proximal structures 5401 and 5402 areadditionally or alternatively coupled using a wireless communicationlink.

In an example, at least one of the distal and proximal structures 5401and 5402 includes or uses a midfield device that is coupled to astent-based or spring-based support, such as described above in theexamples of FIGS. 49-53. In an example, one of the distal and proximalstructures 5401 and 5402 includes a midfield receiver, and the other ofthe structures includes at least one sensor or electrode configured todeliver an electrostimulation therapy.

In an example, the distal and proximal structures 5401 and 5402 areexpandable outside of the cannula 5410. The distal structure 5401 canhave a dedicated first balloon 5441 configured to inflate and expand thedistal structure 5401 when the structure is deployed from the cannula5410. The proximal structure 5402 can similarly have a correspondingdedicated second balloon 5442. In an example, the system 5400 includes asleeve 5450 provided between the distal and proximal structures 5401 and5402. The sleeve 5450 can be configured to buttress or support thevessel between the structures. In an example, one or more active orpassive elements (e.g., sensors and/or electrodes) can be disposed onthe sleeve 5450 and coupled to one or both of the distal and proximalstructures 5401 and 5402.

In an example, the sleeve 5450 diameter is selected such that theassembly comprising the sleeve 5450 and distal structure 5401 advancedby the first push rod 5411 can be held firmly against the cannula 5410.In an example, as the cannula 5410 advances through vasculature (e.g.,over a wire, such as is used for coronary artery stent placement), italso carries the sleeve 5450 and the distal structure 5410. The sleeve5450 and distal structure 5410 can be deployed from the cannula 5410using, e.g., the first push rod 5411 and the first balloon 5441. In anexample, after the distal structure 5401 is deployed and the firstballoon 5441 is deflated, the first push rod 5411 can be furtheradvanced (e.g., up to several additional inches) to release the proximalstructure 5402 from a sleeve of the main cannula 5410. Following thisdeployment, the first push rod 5411 can be withdrawn from the bodyentirely, and one or more sleeve portions of the main cannula 5410 canbe withdrawn with it. Next, the proximal balloon 5442 can be expanded todeploy the proximal structure 5402. In another example, the first andsecond balloons 5441 and 5442 can be provided on a single catheter andpush rod assembly, such as with separate lumens to independently inflatethe balloons.

In examples that include a spring-based or stent-based support ormember, the members can be configured to expand automatically afterdeployment from a cannula. In other examples, a balloon or otherinflation or expansion device can be used together with the variousmembers to expand them into a configuration that can chronically residein a specified vessel location.

In an example, an implantable device is configured for deployment usinga cannula lumen that extends through the vasculature. In some examples,the same or similar intraluminal delivery systems, such as used forvascular stent deployment, can be used to deploy an implantable neuralstimulator as described herein.

FIG. 55 illustrates generally a cross section view of a lumen 5510 thatcan enclose an implantable device 5506 such as can include or use amidfield device, a deployment structure 5520, and an inflatable balloon5525. The implantable device 5506 can be configured for intravasculardeployment using the lumen 5510. In an example, the implantable device5506 can be coupled to, or provided adjacent to, the deploymentstructure 5520 inside of the lumen 5510. The implantable device 5506 canbe configured to ride on an outside portion of the deployment structure5520 as it slides inside of the lumen 5510. In other examples, theimplantable device 5506 can be configured to ride within the deploymentstructure 5520 (e.g., encircled or enclosed at least partially by thedeployment structure 5520), such as displacing a portion of the balloon5525.

FIG. 56 illustrates generally a perspective view of the implantabledevice 5506 and deployment structure 5520 provided outside of a distalend of the lumen 5510. In an example, a push rod 5630 operable by aclinician can be used to adjust a location of the implantable device5506 and deployment structure 5520 in the vasculature at implant.Although illustrated in FIG. 56 as having a coil or spring shape, thedeployment structure 5520 can be any biocompatible structure configuredto retain the implantable device 5506 in a substantially chronicposition within a vessel.

FIG. 57 illustrates generally an example of an implantable device 5706installed in a vessel having a vessel wall 5701. The deploymentstructure 5520 is represented schematically and can have any suitableconstruction or configuration to encourage chronic placement of theimplantable device 5706 against the vessel wall 5701.

In an example, the implantable device 5706 is a midfield deviceconfigured to receive and use energy received wirelessly using midfieldsignals. For example, the midfield device can include an antennaconfigured to receive energy from a propagating field inside of bodytissue. The implantable device 5706 can include a device housing 5760,such as can include a hermetic or otherwise sealed housing structure,and various circuitry, or a hermetically sealed electronics module 5770,disposed inside of the device housing 5760. In an example, theelectronics module 5770 includes one or more of a power storage circuit,a processor circuit, a memory circuit, or other circuit, as similarlydescribed in the example first and second circuitry of FIGS. 27 and 28.In an example, the electronics module 5770 comprises a hermetic,cylindrical electronics housing to minimize its cross-sectional area.The cylindrical housing can be mounted or suspended in a biocompatibleresin or epoxy with smoothed outer edges, such as to make theimplantable package more streamlined and to reduce irritation toadjacent vessel walls. Other hermetic and non-cylindrical housing shapescan similarly be used.

In an example, the implantable device 5706 includes an antenna 5780provided inside of the device housing 5760 but outside of thehermetically sealed electronics module 5770. In an example, theimplantable device 5706 includes at least one and preferably at leasttwo electrodes 5791 and 5792 provided at or near an outer-facing surfaceof the device housing 5760. That is, the electrodes 5791 and 5792 can beconfigured to face outward toward the vessel wall 5701 when theimplantable device 5706 is installed using the deployment structure5520. When properly installed, the electrodes 5791 and 5792 can contactthe vessel wall 5701 to minimize signal transmission or shorting thatcan occur through the blood inside the vessel. Various features can beincorporated with the implantable device 5706 and/or electrodes 5791 and5792 to help encourage the electrodes to maintain contact with thevessel walls. Some examples are shown in FIGS. 59 and 60 and arediscussed below.

In the example of FIG. 57, the implantable device 5706 and deploymentstructure 5520 are configured to expand at least a portion of the vesselwall 5701, such as on one side of the vessel, and thus cause the vesselwall to distend or bulge slightly. By providing the implantable device5706 in a bulged portion of the vessel, a central open area of thevessel can be provided to maintain blood flow therethrough.

FIG. 58 illustrates generally an example of a second implantable device5801 configured similarly to the implantable device 5506 and/or 5706 butincluding an antenna 5880 that can extend outside of the device housing5760. For example, the antenna 5880 can be a rigid or flexible structurethat can reside inside the vessel after implant. Since the antenna 5880is not constrained to being inside of, or contained within the devicehousing 5760, the antenna 5880 can be substantially longer or largerthan the housing portion of the implant.

FIG. 59 illustrates generally a perspective view of an example of afirst electrode assembly coupled to a hermetically sealed electronicsmodule 5970 for an intravascular implantable device. The electrodeassembly is configured to encourage contact between a vessel wall andone or more electrodes. In an example, the electrode assembly includes acurved surface with one or more discrete conductive areas or electrodes.In an example, the curved surface can be selected to match a curvatureof an interior vessel wall, or the surface can be flexible and canconform to a wall curvature. In examples with two or more electrodes, anon-conductive portion of the curved surface can be provided between theelectrodes. In the example of FIG. 59, first and second electrodes 5991and 5992 can be provided at opposite sides of a nonconductive membrane5901 that separates the electrodes. The membrane 5901 can comprisevarious biocompatible materials and can be solid, barbed, or perforated.In an example, the membrane 5901 has a regular or irregular honeycombconfiguration that helps the implant maintain chronic placement in avessel and can, in some examples, integrate itself with the vessel wall.The membrane 5901 can help reduce or minimize current shunting betweenthe first and second electrodes 5991 and 5992, such as by redirectingcurrent through the adjacent vessel wall and toward a neural target.

FIG. 60 illustrates generally a perspective view of an example of asecond electrode assembly coupled to a hermetically sealed electronicsmodule 6070 for an intravascular implantable device. The electronicsmodule 6070 is coupled to first and second electrodes 6091 and 6092 thathave an arcuate shape and extend laterally relative to a body portion ofthe electronics module 6070. The example of FIG. 60 is similar to thatof FIG. 59 but without the membrane 5901 between the electrodes 6091 and6092.

FIG. 61 illustrates generally an example of an intravascular implantabledevice 6106. The example of FIG. 61 includes a hermetic device housingthat encapsulates a hermetically sealed electronics module 6170. Theimplantable device 6106 can include a first electrode 6191 coupled tothe electronics module 6170 and disposed on an outer-facing surface ofthe housing. In an example, the implantable device 6106 includes asecond electrode 6192 provided on a deployment mechanism that can beconfigured to pierce a vessel wall. In an example, the second electrode6192 is located outside of the vessel and therefore can be providedcloser to a therapy target, and can thus be used to deliver a therapy(or sense a physiologic parameter) such as without adverse effects suchas due to a vessel wall being between the electrode and the target.

FIG. 62 illustrates generally a side view of an intravascularimplantable device 6200. In an example, a midfield device can beimplanted or installed and configured to deliver electrostimulation to aneural target using one or more portions of the device 6200. In anexample, the device 6200 can be implanted or installed at leastpartially in the vascular system of a patient. For example, the device6200 can be implanted or installed in an artery. The device 6200 caninclude one or more discrete electrode and/or support portions. In theexample of FIG. 62, the device 6200 includes first, second, third, andfourth portions 6201, 6202, 6203, and 6204, respectively. Each of thefirst through fourth portions 6201-6204 can include or use an electrodeand/or a support for a portion of a midfield device.

In the example of FIG. 62, the third portion 6203 includes a coiledsupport. The coiled support can include an elongated, substantially flatand optionally continuous material that is wound or coiled to aspecified diameter. One or more portions of the coiled support can beconductive and can be coupled to a midfield device for use inphysiologic parameter sensing or electrostimulation. That is, one ormore portions of the coiled support can include or use an electrode. Thecoil diameter can be adjusted, such as at a time of implant or explant.The coil stiffness or material can be selected based on the particularapplication of the device 6200. For example, different materials can beused for renal applications and cardiac applications. The third portion6203 can include a first electrode 6223 that can be coupled to orsupported by the coiled support. The first electrode 6223 can be coupledto a midfield device and can be used for electrostimulation orphysiologic parameter sensing together with drive or sense electronicsincluded in the midfield device.

The example of FIG. 62 as illustrated includes four discrete portions;additional or fewer portions can be used, such as to provide amulti-polar electrostimulation or sensing device. A coupling wire 6213can be used to couple adjacent ones of the portions of the implantabledevice 6200. In an example, the coupling wire 6213 is a seriesconnection between adjacent portions of the device, and in otherexamples, different coupling wires can extend in parallel from each ofthe first through fourth portions 6201-6204 to another portion of amidfield device.

FIG. 63 illustrates generally a perspective view of a secondintravascular implantable device 6300. The second intravascularimplantable device 6300 can include a coiled portion and one or morediscrete support and/or electrode portions as similarly described abovein the example of FIG. 62.

The second intravascular implantable device 6300 includes a firstportion 6301 with a coiled support, and one or more portions of thesupport can be conductive and/or configured for use as an electrode. Inan example, the first portion 6301 includes a discrete electrodeextension 6302. The electrode extension 6302 can be curved to follow aninner wall shape of a vessel in which the device 6300 is installed. Inan example, the first portion 6301 includes one or more tines, such as afirst tine 6303. The first tine 6303 can extend orthogonally to alongitudinal axis of the coiled support. In an example, the first tine6303 is configured to impinge on or pierce an interior vessel wall. Thefirst tine 6303 can thus be used to anchor or fixate the implantabledevice 6300 at a particular specified location within a patient'svasculature. In an example, the first tine 6303 includes one or moreconductive portions and can be used as an electrode when coupled to amidfield device.

FIG. 64 illustrates generally a perspective view of a thirdintravascular implantable device 6400. The third intravascularimplantable device 6400 can include a coiled portion and one or morediscrete support and/or electrode portions as similarly described abovein the examples of FIGS. 62 and/or 63. In the example of FIG. 64, afirst portion 6401 of the device 6400 includes an extension member 6403.In an example, the extension member 6403 extends substantially parallelto an axis of the third device's coiled support. The extension member6403 can be configured to be deployed outside of a vessel wall, such asadjacent to the first portion 6401 of the device 6400. The extensionmember 6403 can help anchor or fixate the implantable device 6400 at aparticular specified location within a patient's vasculature. In anexample, the extension member 6403 includes one or more conductiveportions and can be used as an electrode when coupled to a midfielddevice.

FIG. 65 illustrates generally an example 6500 of a midfield device 6501coupled to the intravascular implantable device 6300. The midfielddevice 6501 can include an antenna 6511 configured to receive wirelessmidfield power and/or data signals, and a body portion 6512 thatencloses telemetry, processing, and drive circuits, as similarlydescribed elsewhere herein for implantable midfield devices.

The midfield device 6501 can further include an interconnect portion6513 configured to be coupled to one or more electrodes deployed in avessel. The midfield device 6501 can, in an example, receive a wirelesspower signal and, in response, use one or more electrodes on theimplantable device 6300 to provide an electrostimulation therapy or tosense a physiologic parameter from a patient. In the example of FIG. 65,the midfield device 6501 is coupled to each portion of the implantabledevice 6300 using a serial connection. That is, a common conductorcouples each electrode portion of the four illustrated portions of thedevice 6300 to the midfield device 6501. In other examples, a parallelconnection can be used, such as to provide separate signals from themidfield device 6501 to the different discrete portions of the device6300.

FIG. 66 illustrates generally an example 6600 of the midfield device6501 coupled to the intravascular implantable device 6300 inside of avessel. The vessel walls 6601 are indicated by dashed lines. The coiledportions of the device 6300 abut or contact the vessel walls 6601. Inthe example of FIG. 66, tines from the device 6300 pierce the vesselwalls 6601 at each of the different discrete coiled portions of thedevice 6300. As explained above, the tines can be used to fixate thedevice 6300 inside of the vessel, and/or the tines can include one ormore conductive portions or electrodes for sensing a physiologicparameter or providing an electrostimulation to the patient. The variouselectrodes can be separately or commonly addressed by drive circuitryinside the midfield device 6501. In the example of FIG. 66, the midfielddevice 6501 is coupled to a central portion of the intravascularimplantable device 6300, with conductors extending from the centralportion of the device 6300 to the distal portions of the device 6300 toeither side of the midfield device 6501.

Any one or more of the fixation features described herein can include acontingency (device, feature, mechanism, etc.) to pull backwards, todeflate, or to contract the device to a smaller diameter to allow forretrieval, explant (e.g., through the same vessel implant path), and/oradjustment of a placement of the various intravascular devices describedherein.

Although the preceding discussion was generally directed tomidfield-powered electrostimulation devices that are configured forrenal nerve stimulation, the midfield-powered electrostimulation devicesand features discussed herein can be deployed in other blood vessels orbody locations. That is, the systems and methods discussed herein can beused to provide electrostimulation therapy to targets throughout thebody, such as by locating chronically placed implantable devices in thevasculature at or near a particular target. In addition to renal systemtargets, other targets accessible from the vasculature can include apatient's phrenic nerves, splanchnic nerves, genital nerves, vagusnerve, or various receptors or targets in the gastrointestinal tract.

In an example, a midfield device can be deployed in a vessel that is inor near a patient's brain. Such a device can be configured to deliverelectrostimulation to a neural brain target, or can be configured tosense brain activity. In an example, a midfield sensor device can recordor archive measured neural activity information and report theinformation, in real-time or otherwise, to an external device, such asusing midfield or other communication techniques.

II. Layered Midfield Transmitter Systems and Devices

In an example, a midfield transmitter device, such as corresponding tothe external source 102 of the example of FIG. 1, can include a layeredstructure with multiple tuning elements. The midfield transmitter can bea dynamically configurable, active transceiver that is configured toprovide RF signals to modulate an evanescent field at a tissue surfaceand thereby generate a propagating field within tissue, such as totransmit power and/or data signals to an implanted target device.

In an example, a midfield transmitter device includes a combination oftransmitter and antenna features. The device can include a slot or patchantenna with a back plane or ground plane, and can include one or moremicrostrips or other device excitation features. In an example, thedevice includes one or more conductive plates that can be excited andthereby caused to generate a signal, such as in response to excitationof one or more corresponding microstrips.

FIG. 67 illustrates generally a top view of an example of a first layer6701A of a layered first transmitter 6700. The first transmitter 6700 isillustrated as circular, however other shapes and profiles for thetransmitter and various transmitter elements or layers can be similarlyused. The first layer 6701A includes a conductive plate that can beetched or cut to provide various layer features. In the example of FIG.67, the first layer 6701A includes a copper substrate that is etchedwith a circular slot 6710 to separate a conductive outer region 6705from a conductive inner region 6715. In this example, the outer region6705 includes a ring or annular feature that is separated by thecircular slot 6710 from a disc-shaped feature comprising the innerregion 6715. That is, the conductive inner region 6715 is electricallyisolated from the conductive annulus comprising the outer region 6705.When the first transmitter 6700 is excited using one or more microstripfeatures, such as can be provided on a different device layer than isillustrated in FIG. 67, such as discussed below, the conductive innerregion 6715 produces a tuned field, and the outer annulus or outerregion 6705 can be coupled to a reference voltage or ground.

The example of FIG. 67 includes multiple tuning features with physicaldimensions and locations with respect to the first layer 6701A toinfluence a field transmitted by the first transmitter 6700. In additionto the etched circular slot 6710, the example includes four radialslots, or arms 6721A, 6721B, 6721C, and 6721D, that extend from thecircular slot 6710 toward the center of the first layer 6701A. Fewer oradditional tuning features, such as having the same shape as illustratedor another shape, can similarly be used to influence a resonantfrequency of the device. That is, although linear radial slots areshown, one or more differently shaped slots can similarly be used.

A diameter of the first layer 6701A and the slot 6710 dimensions can beadjusted to tune or select a resonant frequency of the device. In theexample of FIG. 67, as the length of the arms 6721A-6721D increases, aresonance or center operating frequency decreases. Dielectriccharacteristics of one or more layers adjacent or near to the firstlayer 6701A can also be used to tune or influence a resonance ortransmission characteristic. In the example of FIG. 67, the arms6721A-6721D are substantially the same length. In an example, the armscan have different lengths. Orthogonal pairs of the arms can havesubstantially the same or different length characteristics. In anexample, the first and third arms 6721A and 6721C have a first lengthcharacteristic, and the second and fourth arms 6721B and 6721D can havea different second length characteristic. Designers can adjust the armlengths to tune a device resonance and current distribution pattern.

In an example, capacitive elements can be provided to bridge the slot6710 in one or more places, such as to further tune an operatingfrequency of the transmitter. That is, respective plates of a capacitorcan be electrically coupled to the outer region 6705 and the innerregion 6715 to tune the device.

Dimensions of the first layer 6701A can vary. In an example, an optimalradius is determined by a desired operating frequency, characteristicsof nearby or adjacent dielectric materials, and excitation signalcharacteristics. In an example, a nominal radius of the first layer6701A is about 25 to 45 mm, and a nominal radius of the slot 6710 isabout 20 to 40 mm. In an example, a transmitter device comprising thefirst layer 6701A can be made smaller at a cost of device efficiency,such as by decreasing the slot radius and/or increasing the length ofthe arms.

FIG. 68A illustrates generally a top view of a second layer 6801superimposed over the first layer 6701A of the layered first transmitter6700. The second layer 6801 is spaced apart from the first layer 6701A,such as using a dielectric material interposed therebetween. In anexample, the second layer 6801 includes multiple microstrips configuredto excite the first transmitter 6700. The example of FIG. 68A includesfirst through fourth microstrips 6831A, 6831B, 6831C, and 6831D,corresponding respectively to the four regions of the conductive innerregion 6715 of the first layer 6701A. In the example of FIG. 68A, themicrostrips 6831A-6831D are oriented at about 45 degrees relative torespective ones of the arms 6721A-6721D. Different orientations oroffset angles can be used. Although the example of FIG. 68A shows themicrostrips 6831A-6831D spaced at equal intervals about the circulardevice, other non-equal spacings can be used. In an example, the devicecan include additional microstrips or as few as one microstrip.

The first through fourth microstrips 6831A-6831D provided on the secondlayer 6801 are electrically isolated from the first layer 6701A thatincludes the conductive annular outer region 6705 and the disc-shapedconductive inner region 6715. That is, a dielectric material can beinterposed between the first and second layers 6701A and 6801 of thefirst transmitter 6700.

In the example of FIG. 68A, the first through fourth microstrips6831A-6831D are coupled to respective first through fourth vias6832A-6832D. The first through fourth vias 6832A-6832D can beelectrically isolated from the first layer 6701A, however, in someexamples the first through fourth vias 6832A-6832D can extend throughthe first layer 6701A.

In an example, one or more of the first through fourth microstrips6831A-6831D can be electrically coupled to the conductive inner region6715 of the first layer 6701A, such as using respective other vias thatare not illustrated in the example of FIG. 68A. Such electricalconnections are unnecessary to generate midfield signals using thedevice, however, may be useful for tuning performance of the device.

Various benefits are conferred by providing excitation microstrips, suchas the first through fourth microstrips 6831A-6831D, on a layer thatextends over the conductive inner region 6715 of the first layer 6701A.For example, an overall size of the first transmitter 6700 can bereduced. Various different dielectric materials can be used between thefirst and second layers 6701A and 6801 to reduce a size or thickness ofthe first transmitter 6700.

FIG. 68B illustrates generally a top view of the second layer 6801superimposed over a different first layer 6701B of a layeredtransmitter. Relative to FIG. 68A, the example of FIG. 68B includes thedifferent first layer 6701B instead of the first layer 6701A thatincludes the arms 6721A-6721D. The different first layer 6701B includesa copper substrate that is etched with a circular slot 6810 to separatea conductive outer region from a conductive inner region. In addition tothe etched circular slot 6810, the example includes a pair of linearslots 6811 arranged in an “X” and configured to cross at the centralaxis of the device. The example thus includes, on the different firstlayer 6701B, eight regions that are electrically decoupled, includingfour equally-sized sectors, or pie-piece shaped regions, and fourequally-sized portions of an annulus.

In the example of FIG. 68B, the pair of linear slots 6811 extends toopposite side edges of the substrate or layer. When the device isexcited (e.g., using the microstrips on the second layer 6801), theresulting current density across or over the different first layer 6701Bis more concentrated at the outer annulus portions of the layer than atthe inner sector portions of the layer. The device's operating frequencyor resonance can be determined based on the area of the outer annulus,such as rather than being based on the length of the arms 6721A-6721Dfrom the example of FIG. 68A. Total signal transfer efficiency from atransmitter using the embodiment of FIG. 68B to an implanted midfieldreceiver is similar to the efficiency from a transmitter using theembodiment of FIG. 68A, however, greater current density at the outerannulus portion of the embodiment of FIG. 68B can allow for greatersteerability (that is, transmitted field steering) and thus potentiallybetter access and transmission characteristics for communication withthe implanted midfield receiver when the receiver is off-axis relativeto the transmitter. Furthermore, the specific absorption rate (SAR) canbe reduced when the embodiment of FIG. 68B is used, and unwantedcoupling between ports can be reduced.

FIG. 69 illustrates generally a perspective view of an example of thelayered first transmitter 6700. FIG. 70 illustrates generally a side,cross-section view of the layered first transmitter 6700. The examplesinclude, at the bottom side of each of FIGS. 69 and 70, the first layer6701A of the first transmitter 6700. At the top of the figures, thefirst transmitter 6700 includes a third layer 6901. The third layer 6901can be a conductive layer that provides a shield or backplane for thefirst transmitter 6700. The second layer 6801, such as comprising one ormore microstrips, can be interposed between the first and third layers6701A and 6901. One or more dielectric layers (not illustrated) can beinterposed between the first and second layers 6701A and 6801, and oneor more other dielectric layers can be interposed between the second andthird layers 6801 and 6901.

The examples of FIG. 69 and FIG. 70 include vias that electricallycouple the outer region 6705 on the first layer 6701A with the thirdlayer 6901. That is, ground vias 6941A-6941H can be provided to couple aground plane (e.g., the third layer 6901) with one or more features orregions on the first layer 6701A. In the example, and as describedabove, each of the first through fourth microstrips 6831A-6831D iscoupled to a respective signal excitation via 6832A-6832D. The signalexcitation vias 6832A-6832D can be electrically isolated from the firstand third layers 6701A and 6901.

In the examples of FIG. 69 and FIG. 70, the transmitting side of theillustrated device is downward. That is, when the first transmitter 6700is used and positioned against or adjacent to a tissue surface, thetissue-facing side of the device is the downward direction in thefigures as illustrated.

Providing the third layer 6901 as a ground plane confers variousbenefits. For example, other electronic devices or circuitry can beprovided on top of the third layer 6901 and can be operated withoutunduly interfering with the transmitter. In an example, other radiocircuitry (e.g., operating outside of the range of the midfieldtransmitter) can be provided over the third layer 6901, such as forradio communication with an implanted or other device (e.g., theimplantable device 110, or other implantable device as describedherein). In an example, a second transmitter can be provided, such as ina back-to-back relationship with the first transmitter 6700, and can beseparated from the first transmitter 6700 using the ground plane of thethird layer 6901.

FIG. 71 illustrates generally a top view of an example of a layeredsecond transmitter 7100. The second transmitter 7100 is similar to thefirst transmitter 6700 in profile and in its layered structure. Thesecond transmitter 7100 includes microstrip excitation elements7131A-7131D on a second layer that is offset from a first layer 7101that includes first through fourth patch-like features 7151A-7151D. FIG.72 illustrates generally a perspective view of the layered secondtransmitter 7100.

In the example of FIG. 71, the first layer 7101 includes a conductiveplate that can be etched or cut to provide various layer features. Thefirst layer 7101 includes a copper substrate that is etched to formseveral discrete regions. In the example of FIG. 71, the etchingspartially separate the layer into quadrants. Unlike the examples ofFIGS. 67-69, however, the etched portion does not create a physicallyisolated inner region. Instead, the example of FIG. 71 includes apattern of vias 7160 that are used to partially electrically separatethe discrete regions. The vias 7160 are coupled to another layer thatserves as a ground plane. In the illustrated example, the vias 7160 arearranged in an “X” pattern corresponding to and defining the quadrants.In an example, the vias 7160 extend between the first layer 7101 and asecond layer 7103, and the vias 7160 can be electrically isolated fromanother layer that comprises one or more microstrips. The arrangement ofthe vias 7160 divides the first layer 7101 into substantiallyseparately-excitable quadrants.

The etched portions of the first layer 7101 include various linearslots, or arms, that extend from the outer portion of the first layertoward the center of the device. Similarly to the example of FIGS.67-69, a diameter of the second transmitter device and the slot or armdimensions can be adjusted to tune or select a resonant frequency of thedevice. Dielectric characteristics of one or more layers adjacent ornear to the first layer 7101 can also be used to tune or influence atransmission characteristic of the second transmitter 7100.

In the example of FIG. 71, the vias 7160 and via walls provided in the“X” pattern can be used to isolate the different excitation regions, andcan facilitate steering of propagating fields, such as to target animplantable device that is imprecisely aligned with the transmitter.Signal steering can be provided by adjusting various characteristics ofthe excitation signals that are respectively provided to themicrostrips, such as the first through fourth microstrip excitationelements 7131A-7131D. For example, excitation signal amplitude and phasecharacteristics can be selected to achieve a particular transmissionlocalization.

The present inventors have recognized that the vias, such as the vias7160, provide other benefits. For example, the via walls can cause somesignal reflections to and from the excitation, which in turn can providemore surface current and thereby increase an efficiency of signalstransmitted to tissue.

FIG. 73 illustrates generally an example of a cross-section schematicfor a layered transmitter. The schematic can correspond generally to aportion of any one or more of the examples of FIGS. 67-72. In theexample of FIG. 73, a bottom layer 7301 is a conductive first layer,such as copper, and can correspond to, e.g., the first layer 6701A ofthe example of FIG. 67. That is, the bottom layer 7301 in FIG. 73 can bethe etched first layer 6701A in the example of FIG. 67.

Moving upward from the bottom layer 7301, FIG. 73 includes a firstdielectric layer 7302. This first dielectric layer 7302 can include alow-loss dielectric material, preferably with Dk˜3-13. Above the firstdielectric layer 7302 can be a conductive second layer 7303. Theconductive second layer 7303 can include the one or more microstripexcitation features discussed herein.

A second dielectric layer 7304 can be provided above the conductivesecond layer 7303. The first and second dielectric layers 7302 and 7304can include the same or different material, and can have the same ordifferent dielectric properties or characteristics. In an example, thefirst and second dielectric layers 7302 and 7304 can have differentdielectric characteristics and such characteristics are selected toachieve a particular specified device resonance.

In the example of FIG. 73, the second dielectric layer 7304 includesmultiple layers of dielectric material. As the second dielectric layerbecomes thicker, a distance increases between the conductive secondlayer 7303 and a conductive third layer 7305. The conductive third layer7305 can include backplane or ground. As the distance between theconductive second and third layers 7303 and 7305 increases, thebandwidth of the transmitter can correspondingly increase. The greaterbandwidth can allow for greater data throughput, wider operatingfrequency range for frequency hopping, and can also improvemanufacturability by increasing acceptable tolerances.

One or more vias can extend vertically through the layered assembly asillustrated in FIG. 73. For example, a first via 7311 can extendentirely through a vertical height of the device, while a second via7312 can extend partially through the device. The vias can terminate atthe various conductive layers, such as to provide electricalcommunication between the different layers and the drive circuitry orground.

Various other layers can be provided above the conductive third layer7305. For example, multiple layers of copper and/or dielectrics can beprovided, such as can be used to integrate various electronic deviceswith the transmitter. Such devices can include one or more of a signalamplifier, sensor, transceiver, radio, or other device, or components ofsuch devices, such as including resistors, capacitors, transistors, andthe like.

FIG. 74 illustrates generally an example that shows signal or fieldpenetration within tissue 7406. A transmitter, such as corresponding toone or more of the examples of FIGS. 67-73 or other transmitter such asthe external source 102 of FIG. 1 and designated 7402 in this example,is provided at the top of the illustration. When the transmitter 7402 isactivated to manipulate evanescent fields at an airgap 7404 between thetransmitter 7402 and the tissue 7406, a propagating field (asillustrated by the progressive lobes in the figure) is produced thatextends away from the transmitter 7402 and into the tissue 7406 towardthe bottom of the illustration.

FIG. 75 illustrates generally an example that shows surface currentsthat result when a midfield transmitter, such as according to theexamples of FIGS. 67-73, is excited. The surface current pattern closelymimics an oscillatory, optimal distribution to yield an evanescent fieldthat will give rise to propagating fields inside of tissue (see, e.g.,the example of a propagating field in FIG. 74).

In an example, the excitation signals (e.g., provided to themicrostrips) that provide an optimal current pattern include oscillatingsignals provided to oppositely-oriented microstrips (e.g., second andfourth microstrips 6831B and 6831D in the example of FIG. 68A). In anexample, the excitation signals further include signals provided to theorthogonal ports (e.g., first and third microstrips 6831A and 6831C inthe example of FIG. 68A). This type or mode of excitation can be used toefficiently transfer signals to a deeply implanted receiver (e.g., aloop receiver) inside tissue. In an example, the loop receiver can beoriented in parallel with the current direction as illustrated at thecenter of the transmitter.

FIG. 76 illustrates generally an example of a chart 7600 that shows arelationship between coupling efficiency of the orthogonal transmitterports to an implanted receiver with respect to a changing angle orrotation of the implanted receiver. The example illustrates thatweighting the input or excitation signals provided to the orthogonalports (e.g., to the microstrips) can be used to compensate for rotationof the implanted receiver. When the transmitter can compensate for suchvariations in target device location, consistent power can be deliveredto the target device.

In the example of FIG. 76, a first curve 7601 shows an S-parameter, orvoltage ratio of signal at the transmitter and the receiver, when afirst pair of oppositely-oriented (e.g., top/bottom, or left/right)microstrips are excited by an oscillating signal. A second curve 7602shows an S-parameter when a second pair of the oppositely-orientedmicrostrips are excited by an oscillating signal. The first and secondpairs of microstrips are orthogonal pairs. The example illustrates thatsignals provided to the orthogonal pairs can be optimally weighted toachieve consistent powering with different implant angles, such asthrough constructive interference.

The example of FIG. 76 further illustrates that the transmittersdiscussed herein and their equivalents can be used to effectively steeror orient a propagating field such as without moving the transmitter orexternal source device itself. For example, rotational changes in theposition of an implanted receiver can be compensated by weighting thesignals provided to the various microstrips with different phases, suchas to ensure a consistent signal is delivered to the implant. In anexample, weighting can be adjusted based on a sensed or measured signaltransfer efficiency, such as can be obtained using feedback from theimplant itself. Adjusting the excitation signal weighting can change adirection of the transmitter current distribution, which in turn canchange characteristics of the evanescent field outside of the bodytissue.

FIGS. 77A, 77B, and 77C illustrate generally examples of differentpolarizations of a midfield transmitter. In an example, a polarizationdirection of the transmitter can be changed by adjusting a phase and/ormagnitude of an excitation signal provided to one or more of themicrostrips or to other excitation features of a transmitter. Adjustingthe excitation signals changes the current distribution over theconductive portions of the transmitter, and can be used to polarize thetransmitter into or toward alignment with a receiver, such as tooptimize a signal transfer efficiency. An optimal excitation signalconfiguration can be determined using closed loop feedback from theimplanted device. For example, the external device can make a smallchange in signal phases and weighting of the transmissions. The implantcan then use an integrated power meter to measure a strength of areceived signal and communicate information about the strength to theexternal device, such as to determine an effect of the signal phasechange. The system can converge over time using adjustments in bothpositive and negative directions for phase and port weighting betweenorthogonal ports.

The example of FIG. 77A illustrates a near-optimal current distributionin the left and right quadrants of the transmitter. In this example, thetop and bottom microstrips receive a first pair of excitation signalsand the orthogonal microstrips at the left and right can be unused.

The example of FIG. 77B illustrates a near-optimal current distributionthat is rotated about 45 degrees relative to the example of FIG. 77A. Inthis example, all four of the microstrips can be excited by differentexcitation signals, such as with phase offsets.

The example of FIG. 77C illustrates a near-optimal current distributionthat is rotated about 90 degrees relative to the example of FIG. 77A. Inthis example, the left and right microstrips receive a second pair ofexcitation signals and the orthogonal microstrips at the top and bottomare unused.

FIG. 78 illustrates generally an example of a portion of a layeredmidfield transmitter 7800 showing a first layer with a slot 7810. In anexample, the slot separates an outer conductive region 7805 from aninner conductive region 7815 of the first layer. Additionally oralternatively to adding arms or radial slots to tune an operatingfrequency of the transmitter 7800, capacitive elements can be coupledacross opposing conductive sides of the slot 7810, such as to bridge theouter and inner conductive regions 7805 and 7815. In the example of FIG.78, first and second capacitive elements 7801 and 7802 bridge the outerand inner conductive regions 7805 and 7815 at different locations alongthe slot 7810. The capacitive elements for such bridging and tuning cangenerally be in the picofarad range. Other transmitter configurationsand geometries can similarly be used to achieve the same currentdistribution and steerable fields.

FIG. 79 illustrates generally a perspective view of an example of alayered third transmitter 7900. The examples includes, at the bottomside of the illustration, a first layer 7901 of the third transmitter7900. At the top of the figure, the third transmitter 7900 includes asecond layer 7902. The first and second layers 7901 and 7902 can beseparated using a dielectric layer. Similar to the example of FIG. 67,the first layer 7901 can include a slot 7910 that separates, orelectrically isolates, an outer region 7905 of the first layer 7901 froman inner region 7915 of the first layer 7901. The slot 7910 separatesthe annular outer region 7905 (e.g., an outer annular region) from adisc-shaped inner region 7915 (e.g., an inner disc region). In anexample, the second layer 7902 can be a conductive layer that provides ashield or backplane for the third transmitter 7900.

The example of FIG. 79 includes vias 7930A-7930D that electricallycouple the inner region 7915 on the first layer 7901 with drivecircuitry, such as can be disposed on the second layer 7902. Ground vias(not shown) can be used to electrically couple the outer region 7905with the second layer 7902. That is, the example of FIG. 79 can includea transmitter with an inner region 7915 of the first layer 7901 that isexcitable without the use of additional layers and microstrips. In anexample, the first layer 7901 can be tuned or modified, such as byadding one or more arms that extend from the slot 7910 toward a centerof the device. However, the circular slot 7910 can generally be madelarge enough that a suitable operating resonance or frequency can beachieved without using such additional etched or deposited features as aslot.

FIG. 80 illustrates generally a side, cross-section view of the layeredthird transmitter 7900. The example of FIG. 80 illustrates generallythat a dielectric layer 7903 can be provided between the first andsecond layers 7901 and 7902 of the third transmitter 7900. In anexample, a circuit assembly 7950 can be provided adjacent to the thirdtransmitter 7900, and can be coupled with the third transmitter 7900such as using solder bumps 7941, 7942. Using solder bumps can beconvenient to facilitate assembly by using established solder reflowprocesses. Other electrical connections can similarly be used. Forexample, the top and bottom layers can include an edge plating and/orpads to facilitate interconnection of the layers. In such an example,the top layer can optionally be smaller than the bottom layer (e.g., thetop layer can have a smaller diameter than the bottom layer) and opticalverification of the assembly can be performed more easily. In anexample, the third transmitter 7900 can include one or more capacitivetuning elements 8001 coupled with the first layer 7901, such as at oradjacent to the slot 7910.

III. Embodiments of Related Computer Hardware and/or Architecture

FIG. 81 illustrates, by way of example, a block diagram of an embodimentof a machine 8100 upon which one or more methods discussed herein can beperformed or in conjunction with one or more systems or devicesdescribed herein may be used. FIG. 81 includes reference to structuralcomponents that are discussed and described in connection with severalof the embodiments and figures above. In one or more examples, theimplantable device 110, the source 102, the sensor 107, the processorcircuitry 210, the digital controller 548, circuitry in the circuitryhousing 606-606C, system control circuitry, power management circuitry,the controller, stimulation circuitry, energy harvest circuitry,synchronization circuitry, the external device, control circuitry,feedback control circuitry, the implanted device, location circuitry,control circuitry, other circuitry of the implantable device, and/orcircuitry that is a part of or connected to the external source, caninclude one or more of the items of the machine 8100. The machine 8100,according to some example embodiments, is able to read instructions froma machine-readable medium (e.g., a machine-readable storage medium) andto perform any one or more of the methodologies, one or more operationsof the methodologies, or one or more circuitry functions discussedherein, such as the methods described herein. For example, FIG. 81 showsa diagrammatic representation of the machine 8100 in the example form ofa computer system, within which instructions 8116 (e.g., software, aprogram, an application, an applet, an app, or other executable code)for causing the machine 8100 to perform any one or more of themethodologies discussed herein can be executed. The instructionstransform the general, non-programmed machine into a particular machineprogrammed to carry out the described and illustrated functions in themanner described. In alternative embodiments, the machine 8100 operatesas a standalone device or can be coupled (e.g., networked) to othermachines. In a networked deployment, the machine 8100 can operate in thecapacity of a server machine or a client machine in a server-clientnetwork environment, or as a peer machine in a peer-to-peer (ordistributed) network environment. Various portions of the machine 8100can be included in, or used with, one or more of the external source 102and the implantable device 110. In one or more examples, differentinstantiations or different physical hardware portions of the machine8100 are separately implanted at the external source 102 and theimplantable device 110.

In one or more examples, the machine 8100 can comprise, but is notlimited to, a server computer, a client computer, a personal computer(PC), a tablet computer, a laptop computer, a cellular telephone, asmart phone, a mobile device, a wearable device (e.g., a smart watch), asmart home device (e.g., a smart appliance), other smart devices, a webappliance, a network router, a network switch, a network bridge, or anymachine capable of executing the instructions 8116, sequentially orotherwise, that specify actions to be taken by machine 8100. Further,while only a single machine 8100 is illustrated, the term “machine”shall also be taken to include a collection of machines 8100 thatindividually or jointly execute the instructions 8116 to perform any oneor more of the methodologies discussed herein.

The machine 8100 can include processors 8110, memory 8130, or I/Ocomponents 8150, which can be configured to communicate with each othersuch as via a bus 8102. In one or more examples embodiment, theprocessors 8110 (e.g., a Central Processing Unit (CPU), a ReducedInstruction Set Computing (RISC) processor, a Complex Instruction SetComputing (CISC) processor, a Graphics Processing Unit (GPU), a DigitalSignal Processor (DSP), an Application Specific Integrated Circuitry(ASIC), a Radio-Frequency Integrated Circuitry (RFIC), anotherprocessor, or any suitable combination thereof) can include, forexample, processor 8112 and processor 8114 that can execute instructions8116. The term “processor” is intended to include multi-core processorsthat can include two or more independent processors (sometimes referredto as “cores”) that can execute instructions contemporaneously. AlthoughFIG. 81 shows multiple processors, the machine 8100 can include a singleprocessor with a single core, a single processor with multiple cores(e.g., a multi-core process), multiple processors with a single core,multiple processors with multiples cores, or any combination thereof.

The memory/storage 8130 can include a memory 8132, such as a mainmemory, or other memory storage, and a storage unit 8136, bothaccessible to the processors 8110 such as via the bus 8102. The storageunit 8136 and memory 8132 store the instructions 8116 embodying any oneor more of the methodologies or functions described herein. Theinstructions 8116 can also reside, completely or partially, within thememory 8132, within the storage unit 8136, within at least one of theprocessors 8110 (e.g., within the processor's cache memory), or anysuitable combination thereof, during execution thereof by the machine8100. Accordingly, the memory 8132, the storage unit 8136, and thememory of processors 8110 are examples of machine-readable media.

As used herein, “machine-readable medium” means a device able to storeinstructions and data temporarily or permanently and can include, but isnot be limited to, random-access memory (RAM), read-only memory (ROM),buffer memory, flash memory, optical media, magnetic media, cachememory, other types of storage (e.g., Erasable Programmable Read-OnlyMemory (EEPROM)) and/or any suitable combination thereof. The term“machine-readable medium” should be taken to include a single medium ormultiple media (e.g., a centralized or distributed database, orassociated caches and servers) able to store instructions 8116. The term“machine-readable medium” shall also be taken to include any medium, orcombination of multiple media, that is capable of storing instructions(e.g., instructions 8116) for execution by a machine (e.g., machine8100), such that the instructions, when executed by one or moreprocessors of the machine 8100 (e.g., processors 8110), cause themachine 8100 to perform any one or more of the methodologies describedherein. Accordingly, a “machine-readable medium” refers to a singlestorage apparatus or device, as well as “cloud-based” storage systems orstorage networks that include multiple storage apparatus or devices. Theterm “machine-readable medium” excludes signals per se.

The I/O components 8150 can include a wide variety of components toreceive input, provide output, produce output, transmit information,exchange information, capture measurements, and so on. The specific I/Ocomponents 8150 that are included in a particular machine will depend onthe type of machine. For example, portable machines such as mobilephones will likely include a touch input device or other such inputmechanisms, while a headless server machine will likely not include sucha touch input device. It will be appreciated that the I/O components8150 can include many other components that are not shown in FIG. 81.The I/O components 8150 are grouped according to functionality merelyfor simplifying the following discussion and the grouping is in no waylimiting. In various example embodiments, the I/O components 8150 caninclude output components 8152 and input components 8154. The outputcomponents 8152 can include visual components (e.g., a display such as aplasma display panel (PDP), a light emitting diode (LED) display, aliquid crystal display (LCD), a projector, or a cathode ray tube (CRT)),acoustic components (e.g., speakers), haptic components (e.g., avibratory motor, resistance mechanisms), other signal generators, and soforth. The input components 8154 can include alphanumeric inputcomponents (e.g., a keyboard, a touch screen configured to receivealphanumeric input, a photo-optical keyboard, or other alphanumericinput components), point based input components (e.g., a mouse, atouchpad, a trackball, a joystick, a motion sensor, or other pointinginstrument), tactile input components (e.g., a physical button, a touchscreen that provides location and/or force of touches or touch gestures,or other tactile input components), audio input components (e.g., amicrophone), and the like.

In further example embodiments, the I/O components 8150 can includebiometric components 8156, motion components 8158, environmentalcomponents 8160, or position components 8162 among a wide array of othercomponents. For example, the biometric components 8156 can includecomponents to detect expressions (e.g., hand expressions, facialexpressions, vocal expressions, body gestures, or eye tracking), measurephysiologic signals (e.g., blood pressure, heart rate, body temperature,perspiration, or brain waves, neural activity, or muscle activity),identify a person (e.g., voice identification, retinal identification,facial identification, fingerprint identification, orelectroencephalogram based identification), and the like.

The motion components 8158 can include acceleration sensor components(e.g., accelerometer), gravitation sensor components, rotation sensorcomponents (e.g., gyroscope), and so forth. In one or more examples, oneor more of the motion components 8158 can be incorporated with theexternal source 102 or the implantable device 110, and can be configuredto detect motion or a physical activity level of a patient. Informationabout the patient's motion can be used in various ways, for example, toadjust a signal transmission characteristic (e.g., amplitude, frequency,etc.) when a physical relationship between the external source 102 andthe implantable device 110 changes or shifts.

The environmental components 8160 can include, for example, illuminationsensor components (e.g., photometer), temperature sensor components(e.g., one or more thermometer that detect ambient temperature),humidity sensor components, pressure sensor components (e.g.,barometer), acoustic sensor components (e.g., one or more microphonesthat detect background noise), proximity sensor components (e.g.,infrared sensors that detect nearby objects), gas sensors (e.g., gasdetection sensors to detection concentrations of hazardous gases forsafety or to measure pollutants in the atmosphere), or other componentsthat can provide indications, measurements, or signals corresponding toa surrounding physical environment. The position components 8162 caninclude location sensor components (e.g., a Global Position System (GPS)receiver component), altitude sensor components (e.g., altimeters orbarometers that detect air pressure from which altitude can be derived),orientation sensor components (e.g., magnetometers), and the like. Inone or more examples, the I/O component(s) 8150 can be a part of theimplantable device 110 and/or the external source 102.

Communication can be implemented using a wide variety of technologies.The I/O components 8150 can include communication components 8164operable to couple the machine 8100 to a network 8180 or devices 8170via coupling 8182 and coupling 8172 respectively. For example, thecommunication components 8164 can include a network interface componentor other suitable device to interface with the network 8180. In furtherexamples, communication components 8164 can include wired communicationcomponents, wireless communication components, cellular communicationcomponents, Near Field (nearfield) Communication (NFC) components,midfield communication components, farfield communication components,and other communication components to provide communication via othermodalities. The devices 8170 can be another machine or any of a widevariety of peripheral devices.

Moreover, the communication components 8164 can detect identifiers orinclude components operable to detect identifiers. For example, thecommunication components 8164 can include Radio Frequency Identification(RFID) tag reader components, NFC smart tag detection components,optical reader components (e.g., an optical sensor to detectone-dimensional bar codes such as Universal Product Code (UPC) bar code,multi-dimensional bar codes such as Quick Response (QR) code, Azteccode, Data Matrix, Dataglyph, MaxiCode, PDF417, Ultra Code, UCC RSS-2Dbar code, and other optical codes), or acoustic detection components(e.g., microphones to identify tagged audio signals). In addition, avariety of information can be derived via the communication components8164, such as, location via Internet Protocol (IP) geo-location,location via Wi-Fi® signal triangulation, location via detecting a NFCbeacon signal that can indicate a particular location, and so forth.

In some embodiments, the systems comprise various features that arepresent as single features (as opposed to multiple features). Forexample, in one embodiment, the system includes a single external sourceand a single implantable device or stimulation device with a singleantenna. Multiple features or components are provided in alternateembodiments.

In some embodiments, the system comprises one or more of the following:means for tissue stimulation (e.g., an implantable stimulation device),means for powering (e.g., a midfield powering device or midfieldcoupler), means for receiving (e.g., a receiver), means for transmitting(e.g., a transmitter), means for controlling (e.g., a processor orcontrol unit), etc.

Although various general and specific embodiments are described herein,it will be evident that various modifications and changes can be made tothese embodiments without departing from the broader spirit and scope ofthe present disclosure. Accordingly, the specification and drawings areto be regarded in an illustrative rather than a restrictive sense. Theaccompanying drawings that form a part of this application show, by wayof illustration, and not of limitation, specific embodiments in whichthe subject matter can be practiced. The embodiments illustrated aredescribed in sufficient detail to enable those skilled in the art topractice the teachings disclosed herein. Other embodiments can be usedor derived therefrom, such that structural and logical substitutions andchanges can be made without departing from the scope of this disclosure.This Detailed Description, therefore, is not to be taken in a limitingsense, and the scope of various embodiments is defined only by theappended claims, along with the full range of equivalents to which suchclaims are entitled. Specific embodiments or examples are illustratedand described herein, however, it should be appreciated that anyarrangement calculated to achieve the same purpose can be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the above description.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In this document, the terms “including” and “inwhich” are used as the plain-English equivalents of the respective terms“comprising” and “wherein.” Also, in the following claims, the terms“including” and “comprising” are open-ended, that is, a system, device,article, composition, formulation, or process that includes elements inaddition to those listed after such a term in a claim are still deemedto fall within the scope of that claim. Moreover, in the followingclaims, the terms “first,” “second,” and “third,” etc. are used merelyas labels, and are not intended to impose numerical requirements ontheir objects.

The ranges disclosed herein also encompass any and all overlap,sub-ranges, and combinations thereof. Language such as “up to,” “atleast,” “greater than,” “less than,” “between,” and the like includesthe number recited. Numbers preceded by a term such as “about” or“approximately” include the recited numbers. For example, “about 10 kHz”includes “10 kHz.” Terms or phrases preceded by a term such as“substantially” or “generally” include the recited term or phrase. Forexample, “substantially parallel” includes “parallel” and “generallycylindrical” includes cylindrical.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) may be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. The Abstract is provided to allowthe reader to quickly ascertain the nature of the technical disclosure.It is submitted with the understanding that it will not be used tointerpret or limit the scope or meaning of the claims. Also, in theabove Detailed Description, various features may be grouped together tostreamline the disclosure. This should not be interpreted as intendingthat an unclaimed disclosed feature is essential to any claim. Rather,inventive subject matter may lie in less than all features of aparticular disclosed embodiment. Thus, the following claims are herebyincorporated into the Detailed Description as examples or embodiments,with each claim standing on its own as a separate embodiment, and it iscontemplated that such embodiments can be combined with each other invarious combinations or permutations. The scope of the invention(s) andembodiments should be determined with reference to the appended claims,along with the full scope of equivalents to which such claims areentitled.

What is claimed is:
 1. A midfield transmitter comprising: a firstconductive portion provided on a first layer of the transmitter; one ormore microstrips provided on a second layer of the transmitter; a thirdconductive portion provided on a third layer of the transmitter, thethird conductive portion electrically coupled to the first conductiveplane using one or more vias that extend through the second layer; afirst dielectric member interposed between the first and second layers;and a second dielectric member interposed between the second and thirdlayers.
 2. The midfield transmitter of claim 1, wherein the first andsecond dielectric members have different permittivity characteristics.3. The midfield transmitter of claim 2, wherein a thickness of thesecond dielectric member is greater than a thickness of the firstdielectric member.
 4. The midfield transmitter of claim 1, wherein thefirst conductive portion includes an annular outer region electricallycoupled to the third conductive portion, and the first conductiveportion further includes an inner region that is spaced apart from theannular outer region by a first slot.
 5. The midfield transmitter ofclaim 4, comprising slot extension arms that extend from the first slottoward a central axis of the first conductive portion.
 6. The midfieldtransmitter of claim 5, further comprising four slot extension armsspaced about 90 degrees apart and extending at least half way from thefirst slot to the central axis of the first conductive portion.
 7. Themidfield transmitter of claim 5, wherein the slot extension arms have aslot width that is substantially the same as a width of the first slot.8. The midfield transmitter of claim 4, further comprising a capacitorhaving an anode coupled to the inner region of the first conductiveportion and a cathode coupled to the annular region of the firstconductive portion.
 9. The midfield transmitter of claim 1, wherein thefirst conductive portion includes an etched copper layer comprising agrounded first region and a separate second region electrically isolatedfrom the grounded first region, and wherein the one or more microstripsextend from a peripheral portion of the transmitter toward a centralportion of the transmitter and the one or more microstrips are disposedover at least a portion of the second region of the first conductiveportion.
 10. The midfield transmitter of claim 1, wherein the firstconductive portion includes an etched copper layer comprising a groundedfirst region and a separate second region electrically isolated from thegrounded first region, and wherein the separate second region furtherincludes etched features or vias that divide the second region intoquadrants.
 11. The midfield transmitter of claim 1, further comprising asignal generator circuit configured to provide respective excitationsignals to each of the one or more microstrips.
 12. The midfieldtransmitter of claim 11, wherein the signal generator circuit isconfigured to adjust phase or amplitude characteristics of at least oneof the excitation signals to adjust a current distribution about thefirst conductive portion.
 13. The midfield transmitter of claim 1,wherein a surface area of the third conductive portion is the same orgreater than a surface area of the first conductive plane.
 14. Themidfield transmitter of claim 1, wherein the first and third conductiveportions comprise substantially circular and coaxial conductive members.15. The midfield transmitter of claim 1, wherein the first or thirdconductive portions are coupled to a reference voltage or ground. 16.The midfield transmitter of claim 1, wherein the first or seconddielectric member has a dielectric constant Dk value between 3 and 13.17. The midfield transmitter of claim 1, further comprising a pluralityof vias that extend between the first and third conductive portions andare isolated from the second layer, wherein an arrangement of theplurality of vias divides the first conductive portion intoseparately-excitable quadrants, wherein each of the separately-excitablequadrants includes a grounded peripheral region and an inner conductiveregion, and wherein the first conductive portion is etched with one ormore features to isolate at least a portion of the peripheral regionfrom the inner conductive region.
 18. A midfield transmitter comprising:first and second substantially planar, circular, conductive members thatare substantially coaxial and parallel to each other and spaced apart bya first dielectric member, wherein the second conductive member servesas an electrical reference plane of the transmitter; a first pair ofexcitation members interposed on an intermediate layer between theconductive members; and a passive excitation patch coplanar with, oroffset in the coaxial direction from, the first conductive member;wherein the excitation members are electrically isolated from the firstand second conductive members and each other, and wherein the first pairof excitation members are provided at opposite sides of the transmitter.19. A midfield transmitter comprising: a first conductive plane providedon a first layer of the transmitter, the first conductive planecomprising an outer annular region spaced apart from an inner discregion; a second conductive plane provided on a second layer of thetransmitter, the second conductive plane electrically coupled to theouter annular region of the first conductive plane using one or morevias; a first dielectric member interposed between the first and secondconductive planes; multiple signal input ports coupled to the inner discregion of the first conductive plane and coupled to vias that extendthrough and are electrically isolated from the second conductive planeand the first dielectric member; and transmitter excitation circuitrydisposed on a first side of the second layer opposite the first layer,wherein the transmitter excitation circuitry is configured to providedrive signals to the inner disc region using the multiple signal inputports, and wherein the transmitter excitation circuitry is configured tochange phase or amplitude characteristics of at least one of the drivesignals to adjust a current distribution over the first conductiveplane.
 20. The midfield transmitter of claim 19, wherein the firstconductive plane further includes multiple linear slots that extend atleast part way from a perimeter of the disc region to a center of thedisc region, wherein respective length characteristic of the multiplelinear slots tunes a resonance of the transmitter.